Smartphone-Based Radar System for Determining User Intention in a Lower-Power Mode

ABSTRACT

This document describes techniques and systems that enable a smartphone-based radar system for determining user intention in a lower-power mode. The techniques and systems use a radar field to enable the smartphone to accurately determine the presence or absence of a user and further determine the intention of the user to interact with the smartphone. Using these techniques, the smartphone can account for the user&#39;s nonverbal communication cues to determine and maintain an awareness of users in its environment, and only respond to direct interactions once a user has demonstrated an intention to interact, which preserves battery power. The smartphone may determine the user&#39;s intention by recognizing various cues from the user, such as a change in position relative to the smartphone, a change in posture, or by an explicit action, such as a gesture.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 16/166,900, filed Oct. 22, 2018, issued asU.S. Pat. No. 10,788,880 on Sep. 29, 2020, the entire disclosure ofwhich is hereby incorporated by reference.

BACKGROUND

Smartphones have become a nearly essential accessory for both businessand personal life. The applications on smartphones and other electronicdevices provide an ever-increasing variety of productivity,entertainment, and communication features that users interact withregularly. These devices are our almost constant companions at work,play, and home. We communicate with them via voice and touch, and treatthem like a virtual assistant as we use them to schedule meetings andevents, consume digital media, and share presentations and documents. Inthe everyday world, though, communication is more than just the words weuse. A large part of how we communicate, and express our intention tocommunicate, is based on how we perceive and manage our interpersonalspace. People often use changes of spatial relationships (such asinterpersonal distance or orientation) as an implicit form ofcommunication. For instance, we maintain certain distances from othersdepending on familiarity, we orient toward people when addressing them,we move closer to objects we are interested in, and we stand or sitrelative to others depending on the task at hand.

With the aid of machine-learning techniques, smartphone applications andthe smartphones themselves become more familiar with our routines andpreferences and can provide restaurant recommendations, suggest movies,and otherwise independently communicate with us. For all their computingpower and artificial intelligence, however, smartphones are stillreactive communicators. That is, however “smart” a smartphone is, andhowever much we talk to them like they are people, the smartphone isstill dependent on being activated and the user typically has to firstengage the smartphone and make it aware of the user's intention to usethe smartphone before actually interacting with the applications.Consequently, taking advantage of the powerful and interesting featuresof our applications can be inconvenient and frustrating, and we may notrealize the full potential of our electronic devices and applications.

SUMMARY

This document describes techniques and systems that enable asmartphone-based radar system for determining user intention in alower-power mode. The techniques and systems use a radar field to enablea smartphone to accurately determine the presence or absence of a userand further determine the intention of the user to interact with thesmartphone. Using these techniques, the smartphone can account for theuser's nonverbal communication cues to determine and maintain anawareness of users in its environment, and only respond to directinteractions once the user has demonstrated an intention to interact,which preserves battery power. The smartphone may determine the user'sintention by recognizing various cues from the user, such as a change inposition relative to the smartphone, a change in posture, or by anexplicit action, such as a gesture.

Aspects described below include a smartphone comprising a radar system,one or more computer processors, and one or more computer-readablemedia. The radar system is implemented at least partially in hardwareand provides a radar field. The radar system also senses reflectionsfrom an object in the radar field and analyzes the reflections from theobject in the radar field. The radar system further provides, based onthe analysis of the reflections, radar data. The one or morecomputer-readable media include stored instructions that can be executedby the one or more computer processors to implement a persistentradar-based interaction manager. The persistent radar-based interactionmanager maintains the radar system in an idle mode that requires no morethan approximately 30 milliwatts (mW) of power. The persistentradar-based interaction manager also determines, based on a first subsetof the radar data, a presence of the object within an awareness zone ofthe smartphone. In response to determining the presence of the objectwithin the awareness zone, the persistent radar-based interactionmanager causes the radar system to enter an attention mode that requiresno more than approximately 60 mW of power. In response to entering theattention mode, and based on a second subset of the radar data, thepersistent radar-based interaction manager determines an intention levelof the object and, based on the intention level, determines whether theobject intends to interact with the smartphone. In response todetermining that the intention level indicates the object does notintend to interact with the smartphone, the persistent radar-basedinteraction manager causes the radar system to exit the attention modeand enter the idle mode. In response to determining that the intentionlevel indicates the user intends to interact with the smartphone, thepersistent radar-based interaction manager causes the radar system toexit the attention mode and enter an interaction mode that requires nomore than approximately 90 mW of power.

Aspects described below also include a method, implemented in anelectronic device that includes a radar system. The method comprisesproviding, by the radar system, a radar field and sensing, by the radarsystem, reflections from an object in the radar field. The method alsoincludes analyzing the reflections from the object in the radar fieldand providing, based on the analysis of the reflections, radar data. Themethod additionally includes maintaining the radar system in an idlemode that requires no more than approximately 30 milliwatts (mW) ofpower. The method also includes determining, based on a first subset ofthe radar data, a presence of the object within an awareness zone of theelectronic device and, in response to determining the presence of theobject within the awareness zone, causing the radar system to enter anattention mode that requires no more than approximately 60 mW of power.The method additionally includes, in response to entering the attentionmode, and based on a second subset of the radar data, determining anintention level of the object and, based on the intention level,determining whether the object intends to interact with the electronicdevice. The method further includes, in response to determining that theintention level indicates the object does not intend to interact withthe electronic device, causing the radar system to exit the attentionmode and enter the idle mode. The method also includes, in response todetermining that the intention level indicates the user intends tointeract with the electronic device, causing the radar system to exitthe attention mode and enter an interaction mode that requires no morethan approximately 90 mW of power.

Aspects described below also include a method, implemented in anelectronic device that includes a radar system. The method comprisesproviding, by the radar system, a radar field and sensing, by the radarsystem, reflections from an object in the radar field. The method alsoincludes analyzing the reflections from the object in the radar fieldand providing, based on the analysis of the reflections, radar data. Themethod additionally includes maintaining the radar system in alower-power mode that requires no more than approximately 30 milliwatts(mW) of power. The method also includes determining, based on a firstsubset of the radar data, a presence of the object within an awarenesszone of the electronic device and, in response to determining thepresence of the object within the awareness zone, causing the radarsystem to exit the lower-power mode and enter an interaction mode thatrequires no more than approximately 90 mW of power.

Aspects described below also include a system comprising an electronicdevice that includes, or is associated with, a first means. The firstmeans is a means for providing a radar field, sensing reflections froman object in the radar field, analyzing the reflections from the objectin the radar field, and providing, based on the analysis of thereflections, radar data. The system also includes a second means. Thesecond means is a means for maintaining the first means in an idle modethat requires no more than approximately 30 milliwatts (mW) of power.The second means is also a means for determining, based on a firstsubset of the radar data, a presence of the object within an awarenesszone of the electronic device and, in response to determining thepresence of the object within the awareness zone, causing the firstmeans to enter an attention mode that requires no more thanapproximately 60 mW of power. The second means is also a means for, inresponse to entering the attention mode, and based on a second subset ofthe radar data, determining an intention level of the object. The secondmeans is also a means for determining, based on the intention level,whether the object intends to interact with the electronic device and,in response to determining that the intention level indicates the objectdoes not intend to interact with the electronic device, causing thefirst means to exit the attention mode and enter the idle mode. Thesecond means is also a means for, in response to determining that theintention level indicates the user intends to interact with theelectronic device, causing the first means to exit the attention modeand enter an interaction mode that requires no more than approximately90 mW of power.

Other aspects include a method that can be implemented in an electronicdevice that includes a radar system. The method comprises providing, bythe radar system, a radar field and sensing, by the radar system,reflections from an object in the radar field. The method also includesanalyzing the reflections from the object in the radar field andproviding, based on the analysis of the reflections, radar data. Themethod also includes maintaining the radar system in a first power modeand determining, based on a first subset of the radar data and to afirst degree of certainty, a first intention of the object to interactwith the electronic device. The method additionally includes, inresponse to determining the first intention of the object to interactwith the electronic device, causing the radar system to enter a secondpower mode. In response to entering the second power mode, and based ona second subset of the radar data, the method also includes determining,to a second degree of certainty, a second intention of the object tointeract with the electronic device. The method further includes,responsive to determining the second intention of the object to interactwith the electronic device, causing the radar system to enter a thirdpower mode. In response to entering the third power mode, and based on athird subset of the radar data, the method also includes determining, toa third degree of certainty, a third intention of the object to interactwith the electronic device.

This summary is provided to introduce simplified concepts concerning asmartphone-based radar system for determining user intention in alower-power mode, which is further described below in the DetailedDescription and Drawings. This summary is not intended to identifyessential features of the claimed subject matter, nor is it intended foruse in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of one or more aspects of a smartphone-based radar systemfor determining user intention in a lower-power mode are described inthis document with reference to the following drawings. The same numbersare used throughout the drawings to reference like features andcomponents:

FIG. 1 illustrates an example environment in which techniques enabling asmartphone-based radar system for determining user intention in alower-power mode can be implemented.

FIG. 2 illustrates an example implementation of the smartphone of FIG. 1that includes a radar system and can implement a smartphone-based radarsystem for determining user intention in a lower-power mode.

FIG. 3 illustrates an example implementation of the radar system of FIG.2.

FIG. 4 illustrates example arrangements of receiving antenna elementsfor the radar system of FIG. 3.

FIG. 5 illustrates additional details of an example implementation ofthe radar system of FIG. 2.

FIG. 6 illustrates an example scheme that can be implemented by theradar system of FIG. 2.

FIGS. 7-11 depict example methods enabling a smartphone-based radarsystem for determining user intention in a lower-power mode.

FIGS. 12-18 illustrate example implementations of an electronic devicethat can implement additional details of the method of FIGS. 7-11.

FIG. 19 illustrates various components of an example computing systemthat can be implemented as any type of client, server, and/or electronicdevice as described with reference to FIGS. 1-18 to implement, or inwhich techniques may be implemented that enable, a smartphone-basedradar system for determining user intention in a lower-power mode.

DETAILED DESCRIPTION Overview

This document describes techniques and systems that enable asmartphone-based radar system for determining user intention in alower-power mode. As noted, it can be difficult for an electronic deviceto determine a user's intention to interact with the device, which canlimit its responsiveness. While the device can receive and act on directvoice or touch input, humans usually communicate intention using a mixof verbal and nonverbal communication, and current smartphonesunderstand, at most, the verbal portion. Thus, users may not realize thefull potential of their smartphone features because of limitations inrecognizing nonverbal communication. The described techniques andsystems employ a radar system to determine a user's intention tointeract, or not interact, with the electronic device. The user'sintention may be discerned by determining the user's position, theuser's orientation with reference to the device, the user's posture, orother factors. These techniques enable an increased degree ofrefinement, an increased conformity to truth, or both the increaseddegree of refinement and the increased conformity to truth. Because theelectronic device can determine the user's intention while preservingbattery power, interactions may be more convenient and less frustratingbecause the electronic device can anticipate the user's intent and enteran appropriate mode or state to interact and receive input.

Additionally, the techniques and systems can enable the smartphone toreceive gesture input via a natural three-dimensional (3D) gestureinteraction language that can be used to extend the interaction space ofthe smartphone beyond the screen, which provides accessibility in moresituations. A 3D gesture (e.g., a gesture that comprises one or moremovements, in any direction, within a 3D space illuminated by the radarfield), such as swiping or reaching can be used to interact with thesmartphone without touching it. Using 3D gestures, the user can scrollthrough a recipe without touching the screen when hands are dirty, takea selfie from the right distance and angle without stretching orawkwardly pressing a button, or maintain focus on current tasks byenabling a quick gesture that can be used to reduce interruptions bysuppressing alarms, phone calls, or notifications. Thus, the describedtechniques and systems can improve the quality and effectiveness of theuser's experience using convenient and natural 3D gestures and therebyincrease the user's efficiency, workflow, and enjoyment.

Consider a smartphone or other electronic device that includes a radarsystem and an interaction manager that can be used to provide a radarfield near the electronic device and determine when people or otherobjects enter the radar field. For example, the smartphone may be placedon a table or desk by the user while the user performs other tasks. Theinteraction manager and radar system can operate in a persistentlower-power mode that allows the radar system to detect the presence ofa user within a specified distance. When no users are present, theinteraction manager can also put the smartphone in a lower-power state.The interaction manger can also determine whether the user intends tointeract with the smartphone. If the interaction manager determines thatthe user does not intend to interact with the smartphone, theinteraction manager can maintain the interaction manager and radarsystem in the persistent lower-power mode and maintain the smartphone inthe lower-power state until the interaction manager determines that theuser intends to interact with the smartphone. In this example, theinteraction manager can determine whether the user intends to interactby observing the user's body posture and position, such as whether theuser is looking at, turned toward, or reaching for the smartphone. Theexample power-saving mode can include turning off display elements,hiding message previews, hiding notifications, and so forth. When theinteraction manager determines that the user intends to interact withthe smartphone, the radar system and the smartphone can resume fulloperations to enable the user to access all of the features andfunctions of the smartphone.

For example, when the radar system is in the lower-power mode, thesmartphone can also be in a lower-power state by turning off orotherwise reducing the power consumption of various functions such as adisplay, a touchscreen, a microphone, a voice assistant, and so forth.When the radar system detects the user in the area, and determines thatthe user intends to interact with the smartphone, the interactionmanager can automatically restore the smartphone to a fully operationalstate. The smartphone can be presented in a ready-to-use state (e.g.,the user can be automatically authenticated via a radar-basedauthentication system or by another method) or the smartphone can bepresented ready for authentication by the user (e.g., ready to receive apassword, gesture, fingerprint, or other authentication). In this way,the interaction manager can preserve power without reducingfunctionality for the user. Further, the user may enjoy an improvedexperience with the smartphone because the interaction manageranticipates the user's intentions and can present the smartphone in acustomizable state that allows the user to begin interacting with thesmartphone without having to pick up or touch the smartphone and thenwait for the smartphone to come ready.

Some conventional electronic devices may use cameras or proximitysensors (e.g., capacitive sensors) to determine the location of the userand adjust various functions of the electronic device based on theproximity of the user. For example, the electronic device may provideadditional privacy or aesthetic value by turning off a display unlessthe user is within a predetermined distance. The conventional electronicdevice, however, typically cannot distinguish between the mere presenceof the user (or a non-user who just happens to be near the electronicdevice) and the user who intends to interact with the electronic device.Thus, the conventional electronic device uses more power and potentiallyprovides less privacy or aesthetic value because it may turn on when thenon-user is near or when the user is near, but uninterested ininteraction. For example, the user may set the electronic device on thedesk while talking with a guest. A previously set reminder to make adoctor's appointment may be displayed in a manner that allows the guestto see the reminder. Even a quick-acting user may experience frustrationor embarrassment that the private reminder was displayed at aninopportune time. Consistently annoying or inconvenient interactionswith the smartphone can reduce efficiency and the quality of the user'sexperience, or even reduce the likelihood that the user will use somefeatures.

In contrast, the described systems and techniques can improve efficiencyand usability in several areas while preserving battery life. Forinstance, in the example above, the smartphone can determine that theuser is not paying attention to the smartphone (e.g., by determiningthat the user is turned away from the smartphone) and hide the reminder.In this way, the described techniques and systems allow efficient andnatural interaction with the smartphone or other electronic devices. Theuser can enjoy the advantages and conveniences that smartphones provide,while the interaction manager and radar system provide additionalflexibility and enhanced functionality, without excessive powerconsumption. This can improve efficiency and reduce user frustration byreducing the need for the user to adjust reminders, alerts, andnotifications for different social settings while maintaining privacyand reducing interruptions, which can increase the quality of the userexperience. Further, power consumption of the radar system and theelectronic device itself can be substantially less than someconventional techniques that may use an always-on camera (or othersensors or combinations of sensors) to control some display features.These are but a few examples of how the described techniques and devicesmay be used to enable a smartphone-based radar system for determininguser intention in a lower-power mode. Other examples and implementationsof which are described throughout this document. The document now turnsto an example environment, after which example systems, apparatuses,methods, and components are described.

Operating Environment

FIG. 1 illustrates an example environment 100 in which techniquesenabling a smartphone-based radar system for determining user intentionin a lower-power mode can be implemented. The example environment 100includes a smartphone 102, which includes, or is associated with, aradar system 104, a persistent radar-based interaction manager 106(interaction manager 106), and, optionally, one or more non-radarsensors 108 (non-radar sensor 108). The non-radar sensor 108 can be anyof a variety of devices, such as an audio sensor (e.g., a microphone), atouch-input sensor (e.g., a touchscreen), or an image-capture device(e.g., a camera or video-camera).

In the example environment 100, the radar system 104 provides a radarfield 110 by transmitting one or more radar signals or waveforms asdescribed below with reference to FIGS. 3-6. The radar field 110 is avolume of space from which the radar system 104 can detect reflectionsof the radar signals and waveforms (e.g., radar signals and waveformsreflected from objects in the volume of space). The radar system 104also enables the smartphone 102, or another electronic device, to senseand analyze reflections from an object 112 in the radar field 110. Someimplementations of the radar system 104 are particularly advantageous asapplied in the context of smartphones, such as the smartphone 102, forwhich there is a convergence of issues such as a need for low power, aneed for processing efficiency, limitations in a spacing and layout ofantenna elements, and other issues, and are even further advantageous inthe particular context of smartphones for which radar detection of finehand gestures is desired. Although the embodiments are particularlyadvantageous in the described context of the smartphone for which fineradar-detected hand gestures is required, it is to be appreciated thatthe applicability of the features and advantages of the presentinvention is not necessarily so limited, and other embodiments involvingother types of electronic devices may also be within the scope of thepresent teachings.

The object 112 may be any of a variety of objects from which the radarsystem 104 can sense and analyze radar reflections, such as wood,plastic, metal, fabric, a human body, or human body parts (e.g., a foot,hand, or finger of a user of the smartphone 102). As shown in FIG. 1,the object 112 is a user of the smartphone 102 (user 112). Based on theanalysis of the reflections, the radar system 104 can provide radar datathat includes various types of information associated with the radarfield 110 and the reflections from the user 112, as described withreference to FIGS. 3-6 (e.g., the radar system 104 can pass the radardata to other entities, such as the interaction manager 106).

It should be noted that the radar data may be continuously orperiodically provided over time, based on the sensed and analyzedreflections from the object 112 in the radar field 110. A position ofthe object 112 can change over time (e.g., the object 112 may movewithin the radar field 110) and the radar data can thus vary over timecorresponding to the changed positions, reflections, and analyses.Because the radar data may vary over time, the radar system 104 mayprovide radar data that includes one or more subsets of radar data thatcorrespond to different periods of time. For example, the radar system104 may provide a first subset of the radar data corresponding to afirst time-period, a second subset of the radar data corresponding to asecond time-period, and so forth.

The interaction manager 106 can be used to interact with or controlvarious components of the smartphone 102 (e.g., modules, managers,systems, or interfaces). For example, the interaction manager 106 can beused to maintain the radar system 104 in an idle mode. The idle mode isa persistent lower-power radar mode that allows the radar system 104 toscan an environment external to the smartphone 102 and determine apresence of the user 112. The term “persistent,” with reference to theinteraction manager 106, and to the idle mode of the radar system 104,means that no user interaction is required to maintain the radar system104 in the idle mode or to activate the interaction manager 106. In someimplementations, the “persistent” state may be paused or turned off(e.g., by the user 112). In other implementations, the “persistent”state may be scheduled or otherwise managed in accordance with one ormore parameters of the smartphone 102 (or other electronic device). Forexample, the user 112 may schedule the “persistent” state such that itis only operational during daylight hours, even though the smartphone102 is on both at night and during the day. In another example, the user112 may coordinate the “persistent” state with a power-saving mode ofthe smartphone 102.

In the idle mode, the interaction manager 106 can determine the presenceof the user 112 without verbal, touch, or other input by the user. Forexample, while in the idle mode, the interaction manager 106 may use oneor more subsets of the radar data (as described herein), provided by theradar system 104, to determine the presence of the user 112 or of otherobjects that may be within an awareness zone 114 of the smartphone 102.In this way, the interaction manager 106 can provide seamless powermanagement without requiring explicit user input.

In some implementations, the idle mode requires no more thanapproximately 30 milliwatts (mW) of power. In other implementations, theidle mode may require a different amount of power, such as approximatelytwo mW or approximately eight mW. Further, when the interaction manager106 is maintaining the radar system 104 in the idle mode, theinteraction manager 106 may also maintain the smartphone 102 in alower-power state (e.g., a sleep mode or other power-saving mode). Inthis way, by determining whether the user 112 (or another person) isnear the smartphone 102, the interaction manager can help preservebattery power by reducing power consumption when no user is near thesmartphone 102.

The awareness zone 114 is a zone around the radar system 104 withinwhich the interaction manager 106 can accurately determine the presenceof the user 112. The awareness zone 114 may take any of a variety ofshapes and forms. For example, the awareness zone 114 may beapproximately coterminous with the radar field 110 (e.g., the shape ofthe radar field 110 as described, for example, with reference to FIGS. 3and 4). In other cases, the awareness zone 114 may take a shape such asa radius extending from the radar system 104, a volume around the radarsystem 104 (e.g., a sphere, a hemisphere, a partial sphere, a beam, or acone), or a non-uniform shape (e.g., to accommodate interference fromobstructions in the awareness zone). The awareness zone may extend anyof a variety of distances from the radar system 104 such as three,seven, ten, or fourteen feet (or one, two, three, or four meters), andmay coincide with the extent of the radar field 110. In other cases, asshown in FIG. 1, the awareness zone 114 may be less than a maximumextent of the radar field 110. The awareness zone 114 may be predefined,user-selectable, or determined via another method (e.g., based on powerrequirements, remaining battery life, or another factor). In someimplementations, when the interaction manager 106 determines thepresence of the user 112 (or another object) within the awareness zone114, the interaction manager 106 can cause the radar system 104 to exitthe idle mode and enter an interaction mode, which is described indetail below.

Optionally, or in other implementations, when the interaction manager106 determines the presence of the user 112 (or another object) withinthe awareness zone 114, the interaction manager 106 can cause the radarsystem 104 to enter an attention mode. The attention mode is a radarmode that allows the radar system 104 to provide other information aboutobjects within the awareness zone 114. For example, while in theattention mode, the radar system 104 can provide other radar data(including one or more other subsets of the radar data, as describedherein) that can be used to determine an intention level of the user112.

In some implementations, the attention mode requires no more thanapproximately 60 mW of power. In other implementations, the attentionmode may require a different amount of power, such as betweenapproximately eight mW and approximately fifty-five mW or betweenapproximately two mW and approximately twenty mW. When the interactionmanager 106 is maintaining the radar system 104 in the attention mode,the interaction manager 106 may also maintain the smartphone 102 in thelower-power state that may be used with the idle mode, or theinteraction manager 106 may cause the smartphone to exit the lower-powerstate and enter another state (e.g., a wake mode, an active mode, and soforth).

The interaction manager 106 (or another module or entity) can use theintention level to determine whether the user 112 intends to communicateor interact with the smartphone 102. The intention level can bedetermined from a variety of information about the user 112 (within theawareness zone 114) that can be determined based on the other radardata. The interaction manager 106 can determine the intention level ofthe user 112 without verbal, touch, or other input by the user. Forexample, the interaction manager 106 may determine the user's intentionto view, communicate with, or otherwise interact with the smartphone 102by using the other radar data, or one or more other subsets of the otherradar data, to determine the body position or posture of the user 112 inrelation to the smartphone 102.

The determination of the body position and posture of the user 112 mayinclude determining one or more of a variety of different nonverbal bodylanguage cues, body positions, or body postures. The cues, positions andpostures may include an absolute position or distance of the user 112with reference to the smartphone 102, a change in the position ordistance of the user 112 with reference to the smartphone 102 (e.g.,whether the user 112 is moving closer to or farther from the smartphone102), the velocity of the user 112 when moving near the smartphone 102(e.g., whether the user 112 pauses when near the smartphone 102),whether the user 112 turns toward or away from the smartphone 102,whether the user 112 leans toward, waves toward, reaches for, or pointsat the smartphone 102, and so forth.

Consider an example in which the user 112 is moving toward thesmartphone 102. When the user 112 does not slow down and continues pastthe smartphone 102, the interaction manager 106 determines that the user112 does not intend to interact with the smartphone 102. Similarly, whenthe user 112 slows down, or even stops near the smartphone 102, butturns away from the smartphone 102, the interaction manager 106 alsodetermines that the user 112 does not intend to interact with thesmartphone 102. In contrast, when the user 112 stops near the smartphone102 and is turned toward (or is reaching toward) the smartphone 102, theinteraction manager 106 determines that the user 112 intends to interactwith the smartphone 102. In this way, using the different body positionsand postures of the user 112, the interaction manager 106 can accuratelydetermine whether the user 112 intends to interact with the smartphone102.

When the interaction manager 106 determines that the intention level ofthe user 112 indicates that the user 112 does not intend to interactwith the smartphone 102, the interaction manager 106 can cause the radarsystem 104 to exit the attention mode and enter (or re-enter) the idlemode. When the radar system 104 enters the idle mode, the interactionmanager 106 may also cause the smartphone 102 to enter a lower-powerstate (e.g., if the smartphone 102 is in a higher-power state while theradar system is in the attention mode). Thus, the interaction manager106 can use the intention level of the user 112 to help manage the powerconsumption of the radar system 104 and, optionally, the smartphone 102.

Conversely, when the interaction manager 106 determines that theintention level of the user 112 indicates that the user 112 intends tointeract with the smartphone 102, the interaction manager 106 can causethe radar system 104 to exit the attention mode and enter an interactionmode. The interaction mode is a radar mode that allows the radar system104 to provide additional information about objects within the awarenesszone 114. For example, while in the interaction mode, the radar system104 can provide additional radar data (including one or more additionalsubsets of the radar data, as described herein) that can be used toenable the radar system 104 to determine 3D gestures made by the user112 and process the 3D gestures in a way that enables the user 112 tointeract with the smartphone 102 via the 3D gestures. Additionaldescription and examples of how 3D gestures can be used to interact withthe smartphone 102 are described with reference to FIGS. 10-16.

The interaction mode can also provide additional information to the user112. Continuing the example above, in which the user 112 is movingtoward the smartphone 102, assume that a display of the smartphone 102is dimmed (e.g., because the smartphone 102 is in a lower-power state asdescribed above). Additionally assume that the interaction manager 106determines, based on the intention level, that the user 112 intends tointeract with the smartphone 102 (e.g., because the user 112 is stoppednear the smartphone 102). In response, the interaction manager 106 cancause the smartphone 102 to change a state of the display (e.g., toincrease the display brightness of the current screen or change thescreen to display an authentication screen or a smart assistant). Inthis way, the interaction manager 106 can provide the user 112 withtimely access to the smartphone 102 while preserving battery power andproviding increased privacy.

In some implementations, the interaction mode requires no more thanapproximately 90 mW of power. In other implementations, the interactionmode may require a different amount of power, such as approximately 20mW or approximately 55 mW. Further, when the interaction manager 106maintains the radar system 104 in the interaction mode, while the user112 interacts with the smartphone 102, the interaction manager 106 mayalso maintain the smartphone 102 in an appropriate power mode (e.g., afull-power mode, the wake mode or active mode as described withreference to the attention mode, the sleep mode as described withreference to the idle mode, or another power mode). In this way, bydetermining whether the user 112 (or another person) intends to interactwith the smartphone 102, the interaction manager can help preservebattery power by inducing an appropriate power mode for the radar system104, and optionally for the smartphone 102, that is appropriate to thelevel of interaction by the user 112.

The power consumed by the radar system 104 in the idle mode, theattention mode, and the interaction mode can be adjusted using varioustechniques. For example, the radar system 104 can reduce powerconsumption by collecting radar data at different duty cycles (e.g.,lower frequencies may use less power), turning various components offwhen the components are not active, or adjusting a power amplificationlevel. Additional details regarding power management of the radar system104 (and the smartphone 102) are described with reference to FIG. 3.

The interaction manager 106 can also control or communicate with thenon-radar sensor 108. For example, the interaction manager 106 maymaintain the non-radar sensor 108 in a non-operational state when theradar system 104 is in the idle mode. The interaction manager 106 mayalso cause the non-radar sensor 108 to enter an operational state whenthe presence of the user 112 (or another object) within the awarenesszone 114 is determined and the radar system 104 enters the attentionmode. In another example, the interaction manager 106 may maintain thenon-radar sensor 108 in the non-operational state when the radar system104 is in the idle mode and cause the non-radar sensor 108 to enter theoperational state when the interaction manager 106 causes the radarsystem 104 to enter the interaction mode. In this way, by managing theoperation of sensors and components that use battery power and canobserve or record the user 112, the interaction manager 106 can preservebattery life, increase privacy and security, and may improve the user'sexperience with the smartphone 102.

In some implementations, the smartphone 102 may also include, or beassociated with, one or more other modules, interfaces, or systems. Asshown in FIG. 1, the smartphone 102 includes a 3D gesture module 116 anda smartphone power-management interface 118. The 3D gesture module 116can store both information related to determining 3D gestures based onthe radar data and information related to actions that correspond to the3D gestures.

A 3D gesture can be any of a variety of gestures, including a scrollinggesture made by moving a hand above the smartphone 102 along ahorizontal dimension (e.g., from a left side of the smartphone 102 to aright side of the smartphone 102), a waving gesture made by the user'sarm rotating about an elbow, a pushing gesture made by moving the user'shand above the smartphone 102 along a vertical dimension (e.g., from abottom side of the smartphone 102 to a top side of the smartphone 102).Other types of 3D gestures or motions may also be made, such as areaching gesture made by moving the user's hand towards the smartphone102, a knob-turning gesture made by curling fingers of the user's handto grip an imaginary door knob and rotating in a clockwise orcounter-clockwise fashion to mimic an action of turning the imaginarydoor knob, and a spindle-twisting gesture made by rubbing a thumb and atleast one other finger together. Each of these example gesture types maybe detected by the radar system 104.

Based on the radar data, the interaction manager 106 can detect the 3Dgesture by the user 112 and determine (e.g., using the 3D gesture module116) that the gesture corresponds to a particular action of or by thesmartphone 102. The particular action may be any of a variety ofactions, such as activate one or more sensors (e.g., the non-radarsensor 108), interact with an application (e.g., browse for, select, oropen the application), control a user interface for a media player oranother application, frame and take a photograph, interact withreminders or notifications, or manage a phone call. In this way, theradar system 104 can provide touch-free control of the smartphone 102.Exemplary 3D gestures and corresponding actions are described below withreference to FIGS. 10-16.

As described with reference to FIGS. 3-6, the radar system 104 can usethe radar field 110 to sense and analyze reflections from objects in theradar field 110 in ways that enable high resolution and accuracy forboth gesture recognition and body posture. Thus, the 3D gesture may beany of a variety of types of 3D gestures, such as an arm gesture, a handor finger gesture, a micro-gesture, or another type of gesture. Further,3D gestures may be predefined, selected from a list, or customized(e.g., the user may interact with the interaction manager 106 and theradar system 104 to define unique gestures, or combination of gestures,as corresponding to particular actions).

The smartphone power-management interface 118 provides a communicationlink between the smartphone 102 and the interaction manager 106. In someimplementations, the smartphone power-management interface 118 also actsas a communication link between a power manager 320 (described in moredetail with reference to FIG. 3) and the interaction manager 106. Usingthe smartphone power-management interface 118, the interaction manager106 can send and receive updates related to any of a variety ofpower-related features of the smartphone 102 (e.g., a power state, abattery capacity, or a remaining battery level). The smartphonepower-management interface 118 also enables the interaction manager 106to send and receive control signals to the smartphone 102 that can beused to adjust, control, manage, or modify the power-related features(e.g., enter a lower-power state, exit a sleep mode, and so forth). Forexample, as described above, when the interaction manager 106 ismaintaining the radar system 104 in the idle mode, the attention mode,or the interaction mode, the interaction manager 106 may also maintainthe smartphone 102 in an appropriate power mode (e.g., a sleep mode, awake mode, or another power-level mode) that is related to the radarsystem 104 mode. The interaction manager 106 may use the smartphonepower-management interface 118 to perform these functions. Further, insome implementations, the smartphone power-management interface 118 mayalso be used to maintain the non-radar sensor 108 in the non-operationalstate as described above.

As shown in FIG. 1, the 3D gesture module 116 and the smartphonepower-management interface 118 are depicted as part of the interactionmanager 106. In other implementations, however, either or both of the 3Dgesture module 116 and the smartphone power-management interface 118 maybe a separate entity that can be part of, or separate from, thesmartphone 102.

In more detail, consider FIG. 2, which illustrates an exampleimplementation 200 of the smartphone 102 (including the radar system104, the interaction manager 106, and the non-radar sensor 108) that canimplement a smartphone-based radar system for determining user intentionin a lower-power mode. The smartphone 102 of FIG. 2 is illustrated witha variety of example devices, including a smartphone 102-1, a tablet102-2, a laptop 102-3, a desktop computer 102-4, a computing watch102-5, computing spectacles 102-6, a gaming system 102-7, ahome-automation and control system 102-8, and a microwave 102-9. Thesmartphone 102 can also include other devices, such as televisions,entertainment systems, audio systems, automobiles, drones, track pads,drawing pads, netbooks, e-readers, home security systems, and other homeappliances. Note that the smartphone 102 can be wearable, non-wearablebut mobile, or relatively immobile (e.g., desktops and appliances).

It should be noted that exemplary overall lateral dimensions of thesmartphone 102 can be, for example, approximately eight centimeters byapproximately fifteen centimeters. Exemplary footprints of the radarsystem 104 can be even more limited, such as approximately fourmillimeters by six millimeters with antennas included. The requirementof such a limited footprint for the radar system 104, which is needed toaccommodate the many other desirable features of the smartphone 102 insuch a space-limited package (e.g., a fingerprint sensor, the non-radarsensor 108, and so forth) combined with power and processinglimitations, can lead to compromises in the accuracy and efficacy ofradar gesture detection, at least some of which can be overcome in viewof the teachings herein.

The smartphone 102 also includes one or more computer processors 202 andone or more computer-readable media 204, which includes memory media andstorage media. Applications and/or an operating system (not shown)implemented as computer-readable instructions on the computer-readablemedia 204 can be executed by the computer processors 202 to provide someor all of the functionalities described herein. The smartphone 102 mayalso include a network interface 206. The smartphone 102 can use thenetwork interface 206 for communicating data over wired, wireless, oroptical networks. By way of example and not limitation, the networkinterface 206 may communicate data over a local-area-network (LAN), awireless local-area-network (WLAN), a personal-area-network (PAN), awide-area-network (WAN), an intranet, the Internet, a peer-to-peernetwork, point-to-point network, or a mesh network.

Various implementations of the radar system 104 can include aSystem-on-Chip (SoC), one or more Integrated Circuits (ICs), a processorwith embedded processor instructions or configured to access processorinstructions stored in memory, hardware with embedded firmware, aprinted circuit board with various hardware components, or anycombination thereof. The radar system 104 operates as a monostatic radarby transmitting and receiving its own radar signals. In someimplementations, the radar system 104 may also cooperate with otherradar systems 104 that are within an external environment to implement abistatic radar, a multistatic radar, or a network radar. Constraints orlimitations of the smartphone 102, however, may impact a design of theradar system 104. The smartphone 102, for example, may have limitedpower available to operate the radar, limited computational capability,size constraints, layout restrictions, an exterior housing thatattenuates or distorts radar signals, and so forth. The radar system 104includes several features that enable advanced radar functionality andhigh performance to be realized in the presence of these constraints, asfurther described below with respect to FIG. 3. Note that in FIG. 2, theradar system 104 and the interaction manager 106 are illustrated as partof the smartphone 102. In other implementations, either or both of theradar system 104 and the interaction manager 106 may be separate orremote from the smartphone 102.

These and other capabilities and configurations, as well as ways inwhich entities of FIG. 1 act and interact, are set forth in greaterdetail below. These entities may be further divided, combined, and soon. The environment 100 of FIG. 1 and the detailed illustrations of FIG.2 through FIG. 18 illustrate some of many possible environments anddevices capable of employing the described techniques. FIGS. 3-6describe additional details and features of the radar system 104. InFIGS. 3-6, the radar system 104 is described in the context of thesmartphone 102, but as noted above, the applicability of the featuresand advantages of the described systems and techniques are notnecessarily so limited, and other embodiments involving other types ofelectronic devices may also be within the scope of the presentteachings.

FIG. 3 illustrates an example implementation 300 of the radar system 104that can be used to enable a smartphone-based radar system fordetermining user intention in a lower-power mode. In the example 300,the radar system 104 includes at least one of each of the followingcomponents: a communication interface 302, an antenna array 304, atransceiver 306, a processor 308, and a system media 310 (e.g., one ormore computer-readable storage media). The processor 308 can beimplemented as a digital signal processor, a controller, an applicationprocessor, another processor (e.g., the computer processor 202 of thesmartphone 102) or some combination thereof. The system media 310, whichmay be included within, or be separate from, the computer-readable media204 of the smartphone 102, includes one or more of the followingmodules: an attenuation mitigator 314, a digital beamformer 316, anangle estimator 318, or a power manager 320. These modules cancompensate for, or mitigate the effects of, integrating the radar system104 within the smartphone 102, thereby enabling the radar system 104 torecognize small or complex gestures, distinguish between differentorientations of the user, continuously monitor an external environment,or realize a target false-alarm rate. With these features, the radarsystem 104 can be implemented within a variety of different devices,such as the devices illustrated in FIG. 2.

Using the communication interface 302, the radar system 104 can provideradar data to the interaction manager 106. The communication interface302 may be a wireless or wired interface based on the radar system 104being implemented separate from, or integrated within, the smartphone102. Depending on the application, the radar data may include raw orminimally processed data, in-phase and quadrature (I/Q) data,range-Doppler data, processed data including target location information(e.g., range, azimuth, elevation), clutter map data, and so forth.Generally, the radar data contains information that is usable by theinteraction manager 106 for a smartphone-based radar system fordetermining user intention in a lower-power mode.

The antenna array 304 includes at least one transmitting antenna element(not shown) and at least two receiving antenna elements (as shown inFIG. 4). In some cases, the antenna array 304 may include multipletransmitting antenna elements to implement a multiple-inputmultiple-output (MIMO) radar capable of transmitting multiple distinctwaveforms at a time (e.g., a different waveform per transmitting antennaelement). The use of multiple waveforms can increase a measurementaccuracy of the radar system 104. The receiving antenna elements can bepositioned in a one-dimensional shape (e.g., a line) or atwo-dimensional shape for implementations that include three or morereceiving antenna elements. The one-dimensional shape enables the radarsystem 104 to measure one angular dimension (e.g., an azimuth or anelevation) while the two-dimensional shape enables two angulardimensions to be measured (e.g., both azimuth and elevation). Exampletwo-dimensional arrangements of the receiving antenna elements arefurther described with respect to FIG. 4.

FIG. 4 illustrates example arrangements 400 of receiving antennaelements 402. If the antenna array 304 includes at least four receivingantenna elements 402, for example, the receiving antenna elements 402can be arranged in a rectangular arrangement 404-1 as depicted in themiddle of FIG. 4. Alternatively, a triangular arrangement 404-2 or anL-shape arrangement 404-3 may be used if the antenna array 304 includesat least three receiving antenna elements 402.

Due to a size or layout constraint of the smartphone 102, an elementspacing between the receiving antenna elements 402 or a quantity of thereceiving antenna elements 402 may not be ideal for the angles at whichthe radar system 104 is to monitor. In particular, the element spacingmay cause angular ambiguities to be present that make it challenging forconventional radars to estimate an angular position of a target.Conventional radars may therefore limit a field of view (e.g., anglesthat are to be monitored) to avoid an ambiguous zone, which has theangular ambiguities, and thereby reduce false detections. For example,conventional radars may limit the field of view to angles betweenapproximately −45 degrees to 45 degrees to avoid angular ambiguitiesthat occur using a wavelength of 5 millimeters (mm) and an elementspacing of 3.5 mm (e.g., the element spacing being 70% of thewavelength). Consequently, the conventional radar may be unable todetect targets that are beyond the 45-degree limits of the field ofview. In contrast, the radar system 104 includes the digital beamformer316 and the angle estimator 318, which resolve the angular ambiguitiesand enable the radar system 104 to monitor angles beyond the 45-degreelimit, such as angles between approximately −90 degrees to 90 degrees,or up to approximately −180 degrees and 180 degrees. These angularranges can be applied across one or more directions (e.g., azimuthand/or elevation). Accordingly, the radar system 104 can realize lowfalse-alarm rates for a variety of different antenna array designs,including element spacings that are less than, greater than, or equal tohalf a center wavelength of the radar signal.

Using the antenna array 304, the radar system 104 can form beams thatare steered or un-steered, wide or narrow, or shaped (e.g., as ahemisphere, cube, fan, cone, or cylinder). As an example, the one ormore transmitting antenna elements (not shown) may have an un-steeredomnidirectional radiation pattern or may be able to produce a wide beam,such as the wide transmit beam 406. Either of these techniques enablethe radar system 104 to illuminate a large volume of space. To achievetarget angular accuracies and angular resolutions, however, thereceiving antenna elements 402 and the digital beamformer 316 can beused to generate thousands of narrow and steered beams (e.g., 2000beams, 4000 beams, or 6000 beams), such as the narrow receive beam 408.In this way, the radar system 104 can efficiently monitor the externalenvironment and accurately determine arrival angles of reflectionswithin the external environment.

Returning to FIG. 3, the transceiver 306 includes circuitry and logicfor transmitting and receiving radar signals via the antenna array 304.Components of the transceiver 306 can include amplifiers, mixers,switches, analog-to-digital converters, filters, and so forth forconditioning the radar signals. The transceiver 306 can also includelogic to perform in-phase/quadrature (I/Q) operations, such asmodulation or demodulation. The transceiver 306 can be configured forcontinuous wave radar operations or pulsed radar operations. A varietyof modulations can be used to produce the radar signals, includinglinear frequency modulations, triangular frequency modulations, steppedfrequency modulations, or phase modulations.

The transceiver 306 can generate radar signals within a range offrequencies (e.g., a frequency spectrum), such as between 1 gigahertz(GHz) and 400 GHz, between 4 GHz and 100 GHz, or between 57 GHz and 63GHz. The frequency spectrum can be divided into multiple sub-spectrathat have a similar bandwidth or different bandwidths. The bandwidthscan be on the order of 500 megahertz (MHz), 1 GHz, 2 GHz, and so forth.As an example, different frequency sub-spectra may include frequenciesbetween approximately 57 GHz and 59 GHz, 59 GHz and 61 GHz, or 61 GHzand 63 GHz. Multiple frequency sub-spectra that have a same bandwidthand may be contiguous or non-contiguous may also be chosen forcoherence. The multiple frequency sub-spectra can be transmittedsimultaneously or separated in time using a single radar signal ormultiple radar signals. The contiguous frequency sub-spectra enable theradar signal to have a wider bandwidth while the non-contiguousfrequency sub-spectra can further emphasize amplitude and phasedifferences that enable the angle estimator 318 to resolve angularambiguities. The attenuation mitigator 314 or the angle estimator 318may cause the transceiver 306 to utilize one or more frequencysub-spectra to improve performance of the radar system 104, as furtherdescribed with respect to FIGS. 5 and 6.

A power manager 320 enables the radar system 104 to conserve powerinternally or externally within the smartphone 102. In someimplementations, the power manager 320 communicates with the interactionmanager 106 or the smartphone power-management interface 118 to conservepower within either or both of the radar system 104 or the smartphone102. Internally, for example, the power manager 320 can cause the radarsystem 104 to collect data using a predefined power mode or a specificduty cycle. In this case, the power manager 320 dynamically switchesbetween different power modes such that response delay and powerconsumption are managed together based on the activity within theenvironment. In general, the power manager 320 determines when and howpower can be conserved, and incrementally adjusts power consumption toenable the radar system 104 to operate within power limitations of thesmartphone 102. In some cases, the power manager 320 may monitor anamount of available power remaining and adjust operations of the radarsystem 104 accordingly. For example, if the remaining amount of power islow, the power manager 320 may continue operating in a lower-power modeinstead of switching to a higher power mode.

The lower-power mode, for example, may use a lower duty cycle on theorder of a few hertz (e.g., approximately 1 Hz or less than 5 Hz), whichreduces power consumption to a few milliwatts (mW) (e.g., betweenapproximately 2 mW and 8 mW). The higher-power mode, on the other hand,may use a higher duty cycle on the order of tens of hertz (Hz) (e.g.,approximately 20 Hz or greater than 10 Hz), which causes the radarsystem 104 to consume power on the order of several milliwatts (e.g.,between approximately 6 mW and 20 mW). While the lower-power mode can beused to monitor the external environment or detect an approaching user,the power manager 320 may switch to the higher-power mode if the radarsystem 104 determines the user is starting to perform a gesture.Different triggers may cause the power manager 320 to switch between thedifferent power modes. Example triggers include motion or the lack ofmotion, appearance or disappearance of the user, the user moving into orout of a designated region (e.g., a region defined by range, azimuth, orelevation), a change in velocity of a motion associated with the user,or a change in reflected signal strength (e.g., due to changes in radarcross section). In general, the triggers that indicate a lowerprobability of the user interacting with the smartphone 102 or apreference to collect data using a longer response delay may cause alower-power mode to be activated to conserve power.

The power manager 320 can also conserve power by turning off one or morecomponents within the transceiver 306 (e.g., a voltage-controlledoscillator, a multiplexer, an analog-to-digital converter, a phase lockloop, or a crystal oscillator) during inactive time periods. Theseinactive time periods occur if the radar system 104 is not activelytransmitting or receiving radar signals, which may be on the order ofmicroseconds (us), milliseconds (ms), or seconds (s). Further, the powermanager 320 can modify transmission power of the radar signals byadjusting an amount of amplification provided by a signal amplifier.Additionally, the power manager 320 can control the use of differenthardware components within the radar system 104 to conserve power. Ifthe processor 308 comprises a lower-power processor and a higher-powerprocessor (e.g., processors with different amounts of memory andcomputational capability), for example, the power manager 320 can switchbetween utilizing the lower-power processor for low-level analysis(e.g., implementing the idle mode, detecting motion, determining alocation of a user, or monitoring the environment) and the higher-powerprocessor for situations in which high-fidelity or accurate radar datais requested by the interaction manager 106 (e.g., for implementing theattention mode or the interaction mode, gesture recognition or userorientation).

In addition to the internal power-saving techniques described above, thepower manager 320 can also conserve power within the smartphone 102 byactivating or deactivating other external components or sensors that arewithin the smartphone 102. These external components may includespeakers, a camera sensor, a global positioning system, a wirelesscommunication transceiver, a display, a gyroscope, or an accelerometer.Because the radar system 104 can monitor the environment using a smallamount of power, the power manager 320 can appropriately turn theseexternal components on or off based on where the user is located or whatthe user is doing. In this way, the smartphone 102 can seamlesslyrespond to the user and conserve power without the use of automaticshut-off timers or the user physically touching or verbally controllingthe smartphone 102. The described power management techniques can thusbe used to provide various implementations of the idle mode, theattention mode, and the interaction mode, as described herein.

FIG. 5 illustrates additional details of an example implementation 500of the radar system 104 within the smartphone 102. In the example 500,the antenna array 304 is positioned underneath an exterior housing ofthe smartphone 102, such as a glass cover or an external case. Dependingon its material properties, the exterior housing may act as anattenuator 502, which attenuates or distorts radar signals that aretransmitted and received by the radar system 104. The attenuator 502 mayinclude different types of glass or plastics, some of which may be foundwithin display screens, exterior housings, or other components of thesmartphone 102 and have a dielectric constant (e.g., relativepermittivity) between approximately four and ten. Accordingly, theattenuator 502 is opaque or semi-transparent to a radar signal 506 andmay cause a portion of a transmitted or received radar signal 506 to bereflected (as shown by a reflected portion 504). For conventionalradars, the attenuator 502 may decrease an effective range that can bemonitored, prevent small targets from being detected, or reduce overallaccuracy.

Assuming a transmit power of the radar system 104 is limited, andre-designing the exterior housing is not desirable, one or moreattenuation-dependent properties of the radar signal 506 (e.g., afrequency sub-spectrum 508 or a steering angle 510) orattenuation-dependent characteristics of the attenuator 502 (e.g., adistance 512 between the attenuator 502 and the radar system 104 or athickness 514 of the attenuator 502) are adjusted to mitigate theeffects of the attenuator 502. Some of these characteristics can be setduring manufacturing or adjusted by the attenuation mitigator 314 duringoperation of the radar system 104. The attenuation mitigator 314, forexample, can cause the transceiver 306 to transmit the radar signal 506using the selected frequency sub-spectrum 508 or the steering angle 510,cause a platform to move the radar system 104 closer or farther from theattenuator 502 to change the distance 512, or prompt the user to applyanother attenuator to increase the thickness 514 of the attenuator 502.

Appropriate adjustments can be made by the attenuation mitigator 314based on pre-determined characteristics of the attenuator 502 (e.g.,characteristics stored in the computer-readable media 204 of thesmartphone 102 or within the system media 310) or by processing returnsof the radar signal 506 to measure one or more characteristics of theattenuator 502. Even if some of the attenuation-dependentcharacteristics are fixed or constrained, the attenuation mitigator 314can take these limitations into account to balance each parameter andachieve a target radar performance. As a result, the attenuationmitigator 314 enables the radar system 104 to realize enhanced accuracyand larger effective ranges for detecting and tracking the user that islocated on an opposite side of the attenuator 502. These techniquesprovide alternatives to increasing transmit power, which increases powerconsumption of the radar system 104, or changing material properties ofthe attenuator 502, which can be difficult and expensive once a deviceis in production.

FIG. 6 illustrates an example scheme 600 implemented by the radar system104. Portions of the scheme 600 may be performed by the processor 308,the computer processors 202, or other hardware circuitry. The scheme 600can be customized to support different types of electronic devices andradar-based applications (e.g., the interaction manager 106), and alsoenables the radar system 104 to achieve target angular accuraciesdespite design constraints.

The transceiver 306 produces raw data 602 based on individual responsesof the receiving antenna elements 402 to a received radar signal. Thereceived radar signal may be associated with one or more frequencysub-spectra 604 that were selected by the angle estimator 318 tofacilitate angular ambiguity resolution. The frequency sub-spectra 604,for example, may be chosen to reduce a quantity of sidelobes or reducean amplitude of the sidelobes (e.g., reduce the amplitude by 0.5 dB, 1dB, or more). A quantity of frequency sub-spectra can be determinedbased on a target angular accuracy or computational limitations of theradar system 104.

The raw data 602 contains digital information (e.g., in-phase andquadrature data) for a period of time, different wavenumbers, andmultiple channels respectively associated with the receiving antennaelements 402. A Fast-Fourier Transform (FFT) 606 is performed on the rawdata 602 to generate pre-processed data 608. The pre-processed data 608includes digital information across the period of time, for differentranges (e.g., range bins), and for the multiple channels. A Dopplerfiltering process 610 is performed on the pre-processed data 608 togenerate range-Doppler data 612. The Doppler filtering process 610 maycomprise another FFT that generates amplitude and phase information formultiple range bins, multiple Doppler frequencies, and for the multiplechannels. The digital beamformer 316 produces beamforming data 614 basedon the range-Doppler data 612. The beamforming data 614 contains digitalinformation for a set of azimuths and/or elevations, which representsthe field of view for which different steering angles or beams areformed by the digital beamformer 316. Although not depicted, the digitalbeamformer 316 may alternatively generate the beamforming data 614 basedon the pre-processed data 608 and the Doppler filtering process 610 maygenerate the range-Doppler data 612 based on the beamforming data 614.To reduce a quantity of computations, the digital beamformer 316 mayprocess a portion of the range-Doppler data 612 or the pre-processeddata 608 based on a range, time, or Doppler frequency interval ofinterest.

The digital beamformer 316 can be implemented using a single-lookbeamformer 616, a multi-look interferometer 618, or a multi-lookbeamformer 620. In general, the single-look beamformer 616 can be usedfor deterministic objects (e.g., point-source targets having a singlephase center). For non-deterministic targets (e.g., targets havingmultiple phase centers), the multi-look interferometer 618 or themulti-look beamformer 620 are used to improve accuracies relative to thesingle-look beamformer 616. Humans are an example of a non-deterministictarget and have multiple phase centers 622 that can change based ondifferent aspect angles, as shown at 624-1 and 624-2. Variations in theconstructive or destructive interference generated by the multiple phasecenters 622 can make it challenging for conventional radars toaccurately determine angular positions. The multi-look interferometer618 or the multi-look beamformer 620, however, perform coherentaveraging to increase an accuracy of the beamforming data 614. Themulti-look interferometer 618 coherently averages two channels togenerate phase information that can be used to accurately determine theangular information. The multi-look beamformer 620, on the other hand,can coherently average two or more channels using linear or non-linearbeamformers, such as Fourier, Capon, multiple signal classification(MUSIC), or minimum variance distortion less response (MVDR). Theincreased accuracies provided via the multi-look beamformer 620 or themulti-look interferometer 618 enable the radar system 104 to recognizesmall gestures or distinguish between multiple portions of the user.

The angle estimator 318 analyzes the beamforming data 614 to estimateone or more angular positions. The angle estimator 318 may utilizesignal processing techniques, pattern matching techniques, or machinelearning. The angle estimator 318 also resolves angular ambiguities thatmay result from a design of the radar system 104 or the field of viewthe radar system 104 monitors. An example angular ambiguity is shownwithin an amplitude plot 626 (e.g., amplitude response).

The amplitude plot 626 depicts amplitude differences that can occur fordifferent angular positions of the target and for different steeringangles 510. A first amplitude response 628-1 (illustrated with a solidline) is shown for a target positioned at a first angular position630-1. Likewise, a second amplitude response 628-2 (illustrated with adotted-line) is shown for the target positioned at a second angularposition 630-2. In this example, the differences are considered acrossangles between −180 degrees and 180 degrees.

As shown in the amplitude plot 626, an ambiguous zone exists for the twoangular positions 630-1 and 630-2. The first amplitude response 628-1has a highest peak at the first angular position 630-1 and a lesser peakat the second angular position 630-2. While the highest peak correspondsto the actual position of the target, the lesser peak causes the firstangular position 630-1 to be ambiguous because it is within somethreshold for which conventional radars may be unable to confidentlydetermine whether the target is at the first angular position 630-1 orthe second angular position 630-2. In contrast, the second amplituderesponse 628-2 has a lesser peak at the second angular position 630-2and a higher peak at the first angular position 630-1. In this case, thelesser peak corresponds to target's location.

While conventional radars may be limited to using a highest peakamplitude to determine the angular positions, the angle estimator 318instead analyzes subtle differences in shapes of the amplitude responses628-1 and 628-2. Characteristics of the shapes can include, for example,roll-offs, peak or null widths, an angular location of the peaks ornulls, a height or depth of the peaks and nulls, shapes of sidelobes,symmetry within the amplitude response 628-1 or 628-2, or the lack ofsymmetry within the amplitude response 628-1 or 628-2. Similar shapecharacteristics can be analyzed in a phase response, which can provideadditional information for resolving the angular ambiguity. The angleestimator 318 therefore maps the unique angular signature or pattern toan angular position.

The angle estimator 318 can include a suite of algorithms or tools thatcan be selected according to the type of smartphone 102 (e.g.,computational capability or power constraints) or a target angularresolution for the interaction manager 106. In some implementations, theangle estimator 318 can include a neural network 632, a convolutionalneural network (CNN) 634, or a long short-term memory (LSTM) network636. The neural network 632 can have various depths or quantities ofhidden layers (e.g., three hidden layers, five hidden layers, or tenhidden layers) and can also include different quantities of connections(e.g., the neural network 632 can comprise a fully-connected neuralnetwork or a partially-connected neural network). In some cases, the CNN634 can be used to increase computational speed of the angle estimator318. The LSTM network 636 can be used to enable the angle estimator 318to track the target. Using machine learning techniques, the angleestimator 318 employs non-linear functions to analyze the shape of theamplitude response 628-1 or 628-2 and generate angular probability data638, which indicates a likelihood that the user or a portion of the useris within an angular bin. The angle estimator 318 may provide theangular probability data 638 for a few angular bins, such as two angularbins to provide probabilities of a target being to the left or right ofthe smartphone 102, or for thousands of angular bins (e.g., to providethe angular probability data 638 for a continuous angular measurement).

Based on the angular probability data 638, a tracker module 640 producesangular position data 642, which identifies an angular location of thetarget. The tracker module 640 may determine the angular location of thetarget based on the angular bin that has a highest probability in theangular probability data 638 or based on prediction information (e.g.,previously-measured angular position information). The tracker module640 may also keep track of one or more moving targets to enable theradar system 104 to confidently distinguish or identify the targets.Other data can also be used to determine the angular position, includingrange, Doppler, velocity, or acceleration. In some cases, the trackermodule 640 can include an alpha-beta tracker, a Kalman filter, amultiple hypothesis tracker (MHT), and so forth.

A quantizer module 644 obtains the angular position data 642 andquantizes the data to produce quantized angular position data 646. Thequantization can be performed based on a target angular resolution forthe interaction manager 106. In some situations, fewer quantizationlevels can be used such that the quantized angular position data 646indicates whether the target is to the right or to the left of thesmartphone 102 or identifies a 90-degree quadrant the target is locatedwithin. This may be sufficient for some radar-based applications, suchas user proximity detection. In other situations, a larger number ofquantization levels can be used such that the quantized angular positiondata 646 indicates an angular position of the target within an accuracyof a fraction of a degree, one degree, five degrees, and so forth. Thisresolution can be used for higher-resolution radar-based applications,such as gesture recognition, or in implementations of the attention modeor the interaction mode as described herein. In some implementations,the digital beamformer 316, the angle estimator 318, the tracker module640, and the quantizer module 644 are together implemented in a singlemachine learning module.

These and other capabilities and configurations, as well as ways inwhich entities of FIG. 1-6 act and interact, are set forth below. Thedescribed entities may be further divided, combined, used along withother sensors or components, and so on. In this way, differentimplementations of the smartphone 102, with different configurations ofthe radar system 104 and non-radar sensors, can be used to implement asmartphone-based radar system for determining user intention in alower-power mode. The example operating environment 100 of FIG. 1 andthe detailed illustrations of FIGS. 2-6 illustrate but some of manypossible environments and devices capable of employing the describedtechniques.

Example Methods

FIGS. 7-11 depict example methods 700 and 1000, which enable asmartphone-based radar system for determining user intention in alower-power mode. The methods 700 and 1000 can be performed with anelectronic device that uses a radar system to provide a radar field. Theradar field is used to determine a presence of an object in the radarfield. The radar field can also be used to determine an intention levelof the object, and the intention level can be used to determine whetherthe object intends to interact with the electronic device. Based on thedetermination of the object's intention, the electronic device can enterand exit different modes of functionality and power usage.

The method 700 is shown as a set of blocks that specify operationsperformed but are not necessarily limited to the order or combinationsshown for performing the operations by the respective blocks. Further,any of one or more of the operations may be repeated, combined,reorganized, or linked to provide a wide array of additional and/oralternate methods. In portions of the following discussion, referencemay be made to the example operating environment 100 of FIG. 1 or toentities or processes as detailed in FIGS. 2-6, reference to which ismade for example only. The techniques are not limited to performance byone entity or multiple entities operating on one device.

At 702, a radar field is provided. This radar field can be provided byany of a variety of electronic devices (e.g., the smartphone 102described above), that include, or are associated with, a radar system(e.g., the radar system 104) and an interaction manager (e.g., theinteraction manager 106, which may also include either or both of the 3Dgesture module 116 and the smartphone power-management interface 118).Further, the radar field may be any of a variety of types of radarfields, such as the radar field 110 described above.

At 704, reflections from an object in the radar field are sensed by theradar system. The object may be any of a variety of objects, such aswood, plastic, metal, fabric, or organic material (e.g., a person, suchas the object 112 described above, or a body part of a person). Forclarity, the object will be referred to as “the user” or “users” whiledescribing the method 700.

At 706, the reflections from the object in the radar field are analyzed.The analysis may be performed by any of a variety of entities (e.g., theradar system 104, the interaction manager 106, or another entity) andmay include various operations or determinations, such as thosedescribed with reference to FIGS. 3-6.

At 708, based on the analysis of the reflections, radar data is provided(e.g., the radar data described with reference to FIGS. 1-6). The radardata may be provided by any of a variety of entities, such as the radarsystem 104, the interaction manager 106, or another entity. In someimplementations, the radar system may provide the radar data and passthe radar data to other entities (e.g., any of the described radar-basedapplications, interaction managers, or modules). The description of themethod 700 continues in FIG. 8, as indicated by the letter “A” afterblock 708 of FIG. 7, which corresponds to the letter “A” before block710 of FIG. 8.

At 710, the radar system is maintained (e.g., by the interactionmanager) in an idle mode. As noted with reference to FIG. 1, the idlemode can be a lower-power radar mode that requires no more than 30milliwatts (mW) of power. In some implementations, the idle mode mayrequire a different amount of power, such as approximately two mW orapproximately eight mW. Further, when the radar system is maintained inthe idle mode, the interaction manager may also maintain the electronicdevice in a lower-power state (e.g., a sleep mode or other power-savingmode).

At 712, based on a subset of the radar data, a presence of the userwithin an awareness zone of the electronic device is determined. Theawareness zone is a zone around the radar system within which the user'spresence can be accurately determined without verbal, touch, or otherinput by the user (e.g., the awareness zone 114). As noted withreference to FIG. 1, the awareness zone may extend any of a variety ofdistances from the radar system. The presence of the user within theawareness zone may be determined by any of a variety of entities, suchas the interaction manager.

At 714, in response to the determination of the user within theawareness zone, the radar system can enter an attention mode. The radarsystem may be entered into the attention mode by the interaction manageror by another entity. The attention mode is a radar mode that allows theradar system to provide other information about objects within theawareness zone, such as the user. As noted with reference to FIG. 1, theattention mode may require no more than approximately 60 mW of power. Inother implementations, the attention mode may require a different amountof power, such as between approximately eight mW and approximatelyfifty-five mW or between approximately 2 mW and approximately 20 mW.Further, when the radar system is maintained in the attention mode, theelectronic device may be maintained in the lower-power state that may beused with the idle mode, or the electronic device may exit thelower-power state and enter another power state (e.g., a wake mode, anactive mode, and so forth).

At 716, in response to the electronic device entering the attentionmode, and based on another subset of the radar data, an intention levelof the user within the awareness zone is determined. The intention levelcan be determined from a variety of information about the user withinthe awareness zone that can be determined based on the other subset ofthe radar data. For example, while in the attention mode, the radarsystem can provide other radar data (including one or more other subsetsof the radar data) that can be used to determine either or both of thebody position or posture of the user in relation to the electronicdevice (including changes in the user's body position or posture), asdescribed with reference to FIG. 1. The description of the method 700continues in FIG. 9, as indicated by the letter “B” after block 716 ofFIG. 7, which corresponds to the letter “B” before block 718 of FIG. 9.

At 718, based on the intention level, it is determined whether the userintends to interact with the electronic device. For example, asdescribed with reference to FIG. 1, the interaction manager (or anothermodule or entity) can use the intention level (including one or more ofa variety of different nonverbal body language cues, body positions, orbody postures), to determine whether the user intends to communicate orinteract with the electronic device or whether the user does not intendto communicate or interact with the electronic device.

At 720, in response to the determining that the intention levelindicates the user does not intend to interact with the electronicdevice, the radar system can exit the attention mode and enter the idlemode. The mode of the radar system may be changed by the interactionmanager or by another entity. As noted with reference to FIG. 1, whenthe radar system enters (or re-enters) the idle mode, the electronicdevice may also enter a lower-power state. Note that the attention modedescribed in blocks 714-720 is optional. In some implementations, whenthe presence of the user within the awareness zone of the electronicdevice is determined (e.g., at block 712), the radar system may exit theidle mode and enter the interaction mode without entering the attentionmode, as described below.

At 722, in response to determining that the intention level indicatesthe user intends to interact with the electronic device, the radarsystem may exit the attention mode and enter an interaction mode. Asnoted with reference to FIG. 1, the interaction mode may require no morethan approximately 90 mW of power. In other implementations, theinteraction mode may require a different amount of power, such asapproximately 55 mW or approximately 20 mW. Further, when the radarsystem is maintained in the interaction mode (e.g., while the userinteracts with the electronic device), the electronic device may exitthe lower-power state and be maintained in another appropriate powermode, as described with reference to FIG. 1. The radar system may beentered into the interaction mode by the interaction manager or byanother entity.

The interaction mode is a radar mode that allows the radar system toprovide additional information about the user (or other objects) withinthe awareness zone. For example, while in the interaction mode, theradar system can provide additional radar data (including one or moreadditional subsets of the radar data, as described herein) that can beused to enable the radar system to determine 3D gestures made by theuser and process the 3D gestures in a way that enables the user tointeract with the smartphone 102 via the 3D gestures. For example, asdescribed with reference to FIGS. 3-6, the radar system can use theradar field to sense and analyze reflections from objects in the radarfield in ways that enable high resolution and accuracy for both 3Dgesture recognition and for determining body position and posture.

The method 1000 is shown as a set of blocks that specify operationsperformed but are not necessarily limited to the order or combinationsshown for performing the operations by the respective blocks. Further,any of one or more of the operations may be repeated, combined,reorganized, or linked to provide a wide array of additional and/oralternate methods. In portions of the following discussion, referencemay be made to the example operating environment 100 of FIG. 1 or toentities or processes as detailed in FIGS. 2-9, reference to which ismade for example only. The techniques are not limited to performance byone entity or multiple entities operating on one device.

At 1002, a radar field is provided. This radar field can be provided byany of a variety of electronic devices (e.g., electronic devices similarto those described with reference to the method 700 at block 702).

At 1004, reflections from an object in the radar field are sensed by theradar system (e.g., in a manner similar to that described with referenceto the method 700 at block 704). For clarity, the object will bereferred to as “the user” or “users” while describing the method 1000.

At 1006, the reflections from the object in the radar field areanalyzed. The analysis may be performed by any of a variety of entities(e.g., as described with reference to the method 700 at block 706).

At 1008, based on the analysis of the reflections, radar data isprovided (e.g., as described with reference to the method 700 at block708). The description of the method 1000 continues in FIG. 11, asindicated by the letter “A” after block 1008 of FIG. 10, whichcorresponds to the letter “A” before block 1010 of FIG. 11.

At 1010, the radar system is maintained (e.g., by the interactionmanager) in a lower-power mode. The lower-power mode may be the idlemode or the attention mode, as described above, or another lower-powermode. In some implementations, the lower-power mode requires no morethan approximately 30 mW of power (e.g., when the lower-power mode isthe idle mode). In other implementations, the lower-power mode requiresno more than approximately 60 mW of power (e.g., when the lower-powermode is the attention mode). Further, when the radar system ismaintained in the lower-power mode, the interaction manager may alsomaintain the electronic device in a lower-power state (e.g., a sleepmode or other power-saving mode).

At 1012, based on a subset of the radar data, a presence of the userwithin an awareness zone of the electronic device is determined (e.g.,the awareness zone described with reference to the method 700 at block712).

Optionally, at 1014, in response to the determination of the user withinthe awareness zone, the radar system can enter an attention mode. Theradar system may be entered into the attention mode by the interactionmanager or by another entity. The attention mode may be a radar modethat allows the radar system to provide other information about objectsnear the electronic device (e.g., within the awareness zone), such asthe user. In some cases, the attention mode may require no more thanapproximately 60 mW of power. In other implementations, the attentionmode may require a different amount of power, such as betweenapproximately eight mW and approximately fifty-five mW or betweenapproximately 2 mW and approximately 20 mW. Further, when the radarsystem is maintained in the attention mode, the electronic device may bemaintained in the lower-power state that may be used with the idle mode,or the electronic device may exit the lower-power state and enteranother power state (e.g., a wake mode, an active mode, and so forth).Further, in some implementations, an intention level of the user withinthe awareness zone is determined and, based on the intention level, itis determined whether the user intends to interact with the electronicdevice (e.g., as described with reference to the method 700 at blocks716 and 718). In response to the determining that the intention levelindicates the user does not intend to interact with the electronicdevice, the radar system can exit the attention mode and enter the idlemode (e.g., as described with reference to the method 700 at block 720).

At 1016, in response to determining the presence of the user within theawareness zone, the radar system may exit the idle mode and enter aninteraction mode. As noted with reference to FIG. 1, the interactionmode may require no more than approximately 90 mW of power. In otherimplementations, the interaction mode may require a different amount ofpower, such as approximately 55 mW or approximately 20 mW. Further, whenthe radar system is maintained in the interaction mode (e.g., while theuser interacts with the electronic device), the electronic device mayexit the lower-power state and be maintained in another appropriatepower mode, as described with reference to FIG. 1. The radar system maybe entered into the interaction mode by the interaction manager or byanother entity.

Consider, for example, FIG. 12 through FIG. 18, which illustrate exampleimplementations of electronic devices that can implement additionaldetails of the method 700. FIG. 12 depicts an example implementation1200 of the electronic device (in this case, the smartphone 102, whichis in a pocket of a user 1202, who is listening to music with anapplication on the smartphone 102). The smartphone 102 includes theradar system 104, which is providing the radar field 110. In the exampleimplementation 1200, assume that the interaction manager has determinedthat the user 1202 intends to interact with the smartphone 102 (e.g., bydetermining that the user 102 leaned down toward the smartphone 102). Inresponse, the interaction manager is maintaining the radar system in theinteraction mode, so that the user 1202 can interact with the smartphone102. For example, as shown in FIG. 12, the user 1202 is interacting withthe smartphone 102 by making a swiping gesture, shown by an arrow 1204.The swiping gesture can cause the music application on the smartphone102 to skip to the next track.

Other 3D gestures can be used to control other features or applications.For example, a set of 3D gestures can control a playback experience formultimedia applications (e.g., music, video, presentation orcollaboration applications, and games) from a distance. The other 3Dgestures may include an air tap for play/pause, a swipe up or down toadjust volume, a pinch gesture to copy and paste text, or a rotationgesture to select new content. The same types of 3D gestures can be usedin a “cast” context. For example, if the user is casting content toanother device (e.g., a large-screen television), from the smartphone102 (or another device) the user can control the media experience on theother device with 3D gestures via the smartphone 102 in the interactionmode.

Similarly, FIG. 13 depicts an example implementation 1300 of theelectronic device (in this case, the smartphone 102, which is on a tablenear a user 1302). The smartphone 102 includes the radar system 104,which is providing the radar field 110. In the example implementation1300, assume that the user 1302 is mixing wet ingredients in a bowlaccording to a recipe displayed on the smartphone 102 and that both ofthe user's hands are covered with the wet ingredients. Further assumethat the interaction manager has determined that the user 1302 intendsto interact with the smartphone 102 (e.g., by determining that the user1302 leaned and reached toward the smartphone 102). In response, theinteraction manager is maintaining the radar system in the interactionmode, so that the user 1302 can interact with the smartphone 102. Forexample, as shown in FIG. 13, the user 1302 is interacting with thesmartphone 102 by making a reaching gesture, shown by an arrow 1304. Thereaching gesture can cause the smartphone 102 to scroll or advance thedisplayed recipe so that the user 1302 can read the next steps.

FIG. 14 depicts an example implementation 1400 of the electronic device,in this case, the smartphone 102, which is being held up by a user 1402,who is positioning the smartphone 102 to take a photograph with anotheruser 1404 (e.g., a “selfie”). The smartphone 102 includes the radarsystem 104, which is providing the radar field 110. In the exampleimplementation 1000, assume that the interaction manager has determinedthat the user 1404 intends to interact with the smartphone 102 (e.g., bydetermining that the user 102 reached toward the smartphone 102). Inresponse, the interaction manager is maintaining the radar system in theinteraction mode, so that the user 1404 can interact with the smartphone102. For example, as shown in FIG. 14, the user 1404 is interacting withthe smartphone 102 by making a swiping gesture, shown by an arrow 1406.The swiping gesture can cause the smartphone 102 to apply a filter,adjust a zoom level, change a flash setting, and so forth. Other 3Dgestures, such as a tap, twist, or rotation, may control other camerafunctions, allowing the users 1402 and 1404 to comfortably take thephotograph, without over-stretching or posing in an unnatural way inorder to reach the controls.

FIG. 15 depicts an example implementation 1500 of the electronic device(in this case, the smartphone 102, which is being held by a user 1502,who is working on a task that requires using multiple applications onthe smartphone 102). The smartphone 102 includes the radar system 104,which is providing the radar field 110. In the example implementation1500, assume that the interaction manager has determined that the user1002 intends to interact with the smartphone 102 (e.g., by determiningthat the user 102 leaned down toward and picked up the smartphone 102).In response, the interaction manager is maintaining the radar system inthe interaction mode, so that the user 1502 can interact with thesmartphone 102. For example, as shown in FIG. 15, the user 1502 isinteracting with the smartphone 102 by making a swiping gesture, shownby an arrow 1504. The swiping gesture can cause the smartphone 102 toswitch between different applications (e.g., forward and backwardchronologically or in a predefined order).

FIG. 16 depicts an example implementation 1600 of the electronic device(in this case, the smartphone 102, which is on a bedside table near auser 1602). The smartphone 102 includes the radar system 104, which isproviding the radar field 110. In the example implementation 1600,assume that the interaction manager has determined that the user 1002intends to interact with the smartphone 102 (e.g., by determining thatthe user 102 reached toward the smartphone 102). In response, theinteraction manager is maintaining the radar system in the interactionmode, so that the user 1602 can interact with the smartphone 102. Forexample, in FIG. 16, further assume that a morning alarm has awakenedthe user 1602, who is interacting with the smartphone 102 by making aswiping gesture, shown by an arrow 1604. The swiping gesture can causethe smartphone 102 to turn off or delay (e.g., snooze) the alarm so thatthe user 1602 can prepare to get out of bed without having to find atouch input on an alarm interface.

FIG. 17 depicts an example implementation 1700 of the electronic device(in this case, the smartphone 102, which is on a table near a user 1702,who is working on a task that does not require using the smartphone102). The smartphone 102 includes the radar system 104, which isproviding the radar field 110. In the example implementation 1700,assume that the interaction manager has determined that the user 1002intends to interact with the smartphone 102 (e.g., by determining thatthe user 102 reached toward the smartphone 102, even though the user1702 did not turn toward the smartphone 102). In response, theinteraction manager is maintaining the radar system in the interactionmode, so that the user 1702 can interact with the smartphone 102. Forexample, in FIG. 17, further assume that the smartphone 102 is ringing(receiving a phone call), but the user 1702 does not want to beinterrupted. The user 1702 interacts with the smartphone 102 by making aswiping gesture, shown by an arrow 1704. The swiping gesture can causethe smartphone 102 to silence the ringer or send the phone call tovoicemail so that the user 1702 can complete the current task withouthaving to answer the call or find a touch input.

FIG. 18 depicts an example implementation 1800 of the electronic device(in this case, the smartphone 102, which is on a table near a user 1802,who is having a meal with another user 1804). The smartphone 102includes the radar system 104, which is providing the radar field 110.In the example implementation 1800, assume that the interaction managerhas determined that the user 1002 intends to interact with thesmartphone 102 (e.g., by determining that the user 102 reached towardthe smartphone 102, even though the user 1802 did not turn toward thesmartphone 102). In response, the interaction manager is maintaining theradar system in the interaction mode, so that the user 1802 can interactwith the smartphone 102. For example, in FIG. 18, further assume thatthe smartphone 102 is displaying a notification, but the user 1802 doesnot want to be interrupted. The user 1802 interacts with the smartphone102 by making a swiping gesture, shown by an arrow 1806. The swipinggesture can cause the smartphone 102 to hide and postpone thenotification so that the user 1802 can enjoy the meal without having toaddress the notification or find a touch input.

As shown in the examples illustrated in FIGS. 12-18, the techniques ofthe methods 700 and/or 1000 can enable users to interact with thesmartphone 102 without taking the smartphone 102 out of a pocket orother container, or having to touch the smartphone 102. The techniquesthereby provide several advantages. For example, the interaction spaceof the smartphone 102 (and other electronic devices) is extended beyondthe screen, which keeps the electronic devices useful and accessiblewhen a touch screen or other input method would be inconvenient, unsafeor uncomfortable. Further, the techniques allow users to quickly accessand interact with their electronic devices (e.g., silencing alarms oralerts), without getting distracted, so that the users can takeadvantage of updates and information available via the electronicdevices, but remain mostly undistracted as well.

It should be noted that these techniques for a smartphone-based radarsystem for determining user intention in a lower-power mode may be moresecure than other techniques. Not only are 3D gestures (especiallyuser-defined gestures, micro-gestures, and posture- or position-basedgestures) not typically obtainable by an unauthorized person (unlike,for example, a password), but also because a radar image of the user,even if it includes the user's face, does not visually identify the userlike a photograph or video does. Even so, further to the descriptionsabove, the user may be provided with controls allowing the user to makean election as to both whether and when any of the systems, programs,modules, or features described in this document may enable collection ofuser information (e.g., information about a user's social network,social actions or activities, profession, a user's preferences, or auser's current location), and whether the user is sent content orcommunications from a server. In addition, certain data may be treatedin one or more ways before it is stored or used, so that personallyidentifiable information is removed. For example, a user's identity maybe treated so that no personally identifiable information can bedetermined for the user, or a user's geographic location may begeneralized where location information is obtained (such as to a city,zip code, or state level), so that a particular location of a usercannot be determined. Thus, the user may have control over whatinformation is collected about the user, how that information is used,and what information is provided to or about the user.

Example Computing System

FIG. 19 illustrates various components of an example computing system1900 that can be implemented as any type of client, server, and/orelectronic device as described with reference to the previous FIGS. 1-18to implement a smartphone-based radar system for determining userintention in a lower-power mode.

The computing system 1900 includes communication devices 1902 thatenable wired and/or wireless communication of device data 1904 (e.g.,radar data, 3D gesture data, authentication data, reference data,received data, data that is being received, data scheduled forbroadcast, and data packets of the data). The device data 1904 or otherdevice content can include configuration settings of the device, mediacontent stored on the device, and/or information associated with a userof the device (e.g., an identity of a person within a radar field orcustomized gesture data). Media content stored on the computing system1900 can include any type of radar, biometric, audio, video, and/orimage data. The computing system 1900 includes one or more data inputs1906 via which any type of data, media content, and/or inputs can bereceived, such as human utterances, interactions with a radar field,touch inputs, user-selectable inputs (explicit or implicit), messages,music, television media content, recorded video content, and any othertype of audio, video, and/or image data received from any content and/ordata source. The data inputs 1906 may include, for example, theinteraction manager 106, the 3D gesture module 116, or the smartphonepower-management interface 118.

The computing system 1900 also includes communication interfaces 1908,which can be implemented as any one or more of a serial and/or parallelinterface, a wireless interface, any type of network interface, a modem,and as any other type of communication interface. The communicationinterfaces 1908 provide a connection and/or communication links betweenthe computing system 1900 and a communication network by which otherelectronic, computing, and communication devices communicate data withthe computing system 1900.

The computing system 1900 includes one or more processors 1910 (e.g.,any of microprocessors, controllers, or other controllers) that canprocess various computer-executable instructions to control theoperation of the computing system 1900 and to enable techniques for, orin which can be implemented, a smartphone-based radar system fordetermining user intention in a lower-power mode. Alternatively oradditionally, the computing system 1900 can be implemented with any oneor combination of hardware, firmware, or fixed logic circuitry that isimplemented in connection with processing and control circuits, whichare generally identified at 1912. Although not shown, the computingsystem 1900 can include a system bus or data transfer system thatcouples the various components within the device. A system bus caninclude any one or combination of different bus structures, such as amemory bus or memory controller, a peripheral bus, a universal serialbus, and/or a processor or local bus that utilizes any of a variety ofbus architectures.

The computing system 1900 also includes computer-readable media 1914,such as one or more memory devices that enable persistent and/ornon-transitory data storage (i.e., in contrast to mere signaltransmission), examples of which include random access memory (RAM),non-volatile memory (e.g., any one or more of a read-only memory (ROM),flash memory, EPROM, EEPROM, etc.), and a disk storage device. A diskstorage device may be implemented as any type of magnetic or opticalstorage device, such as a hard disk drive, a recordable and/orrewriteable compact disc (CD), any type of a digital versatile disc(DVD), and the like. The computing system 1900 can also include a massstorage media device (storage media) 1916.

The computer-readable media 1914 provides data storage mechanisms tostore the device data 1904, as well as various device applications 1918and any other types of information and/or data related to operationalaspects of the computing system 1900. For example, an operating system1920 can be maintained as a computer application with thecomputer-readable media 1914 and executed on the processors 1910. Thedevice applications 1918 may include a device manager, such as any formof a control application, software application, signal-processing andcontrol modules, code that is native to a particular device, anabstraction module, a gesture recognition module, and other modules. Thedevice applications 1918 may also include system components, engines, ormanagers to implement a smartphone-based radar system for determininguser intention in a lower-power mode, such as the radar system 104, theinteraction manager 106, the 3D gesture module 116, or the smartphonepower-management interface 118. The computing system 1900 may alsoinclude, or have access to, one or more machine learning systems.

CONCLUSION

Although implementations of techniques for, and apparatuses enabling, asmartphone-based radar system for determining user intention in alower-power mode have been described in language specific to featuresand/or methods, it is to be understood that the subject of the appendedclaims is not necessarily limited to the specific features or methodsdescribed. Rather, the specific features and methods are disclosed asexample implementations enabling a smartphone-based radar system fordetermining user intention in a lower-power mode.

1-20. (canceled)
 21. An electronic device, comprising: a radar system,implemented at least partially in hardware, configured to: provide aradar field; sense reflections from an object in the radar field;provide an analysis of the reflections from the object; and provide,based on the analysis of the reflections, radar data; and one or morecomputer-readable media having instructions stored thereon that,responsive to execution by one or more computer processors, implement apersistent radar-based interaction manager configured to: maintain theradar system in an idle mode, the idle mode requiring no more than afirst threshold of power; determine, based on a first subset of theradar data, whether a presence of the object is within an awareness zoneof the electronic device; responsive to a determination that the objectis within the awareness zone, cause the radar system to enter anattention mode, the attention mode requiring no more than a secondthreshold of power, the second threshold of power greater than the firstthreshold of power; responsive to an entrance to the attention mode andbased on a second subset of the radar data, determine whether the objectintends or does not intend to interact with the electronic device;responsive to a determination that the object does not intend tointeract with the electronic device, cause the radar system to exit theattention mode and enter the idle mode; and responsive to adetermination that the object intends to interact with the electronicdevice, cause the radar system to exit the attention mode and enter aninteraction mode, the interaction mode requiring no more than a thirdthreshold of power, the third threshold of power greater than the secondthreshold of power.
 22. The electronic device of claim 21, wherein thefirst threshold of power is approximately eight milliwatts (mW) and thethird threshold of power is approximately 55 mW of power.
 23. Theelectronic device of claim 21, wherein the first threshold of power isapproximately two milliwatts (mW) and the third threshold of power isapproximately 20 mW of power.
 24. The electronic device of claim 21,wherein the first threshold of power is approximately one milliwatt (mW)and the third threshold of power is approximately three mW of power. 25.The electronic device of claim 21, wherein the persistent radar-basedinteraction manager is further configured to: adjust a duty cycle atwhich the radar field of the radar system is maintained in the idlemode, the attention mode, or the interaction mode.
 26. The electronicdevice of claim 21, wherein the persistent radar-based interactionmanager is further configured, responsive to a context of the electronicdevice, to power off the radar system.
 27. The electronic device ofclaim 26, wherein: the electronic device comprises a smartphone; and thecontext of the electronic device comprises at least one of thesmartphone being maintained in a power-saving mode, the smartphone beingwithin a time period set by a user of the smartphone to power off theradar system, or the smartphone being placed face down on a surface. 28.The electronic device of claim 21, wherein the persistent radar-basedinteraction manager, in determining whether the object intends or doesnot intend to interact with the electronic device, is configured to:determine, based on the second subset of the radar data, a position orposture of the object in relation to the electronic device.
 29. Theelectronic device of claim 28, wherein the position or posture of theobject in relation to the electronic device comprises at least one of anabsolute position of the object in relation to the electronic device, achange in the absolute position of the object in relation to theelectronic device, a relative velocity of the object in relation to theelectronic device, a change in the relative velocity of the object inrelation to the electronic device, or a change in the posture of theobject in relation to the electronic device.
 30. The electronic deviceof claim 28, wherein: the object comprises a user of the electronicdevice; and the position or posture of the object in relation to theelectronic device comprises at least one of the user moving closer to orfarther from the electronic device, the user pausing near the electronicdevice, the user turning toward or away from the electronic device, theuser leaning toward the electronic device, the user waving toward orreaching for the electronic device, or the user pointing at theelectronic device.
 31. The electronic device of claim 30, wherein thepersistent radar-based interaction manager is further configured to:determine that the user intends to interact with the electronic devicein response to a detection of at least one of the user moving closer tothe electronic device, the user reaching for the electronic device, theuser pausing near the electronic device, the user turning toward theelectronic device, the user leaning toward the electronic device, or theuser pointing at the electronic device.
 32. The electronic device ofclaim 30, wherein the persistent radar-based interaction manager isfurther configured to: determine that the user does not intend tointeract with the electronic device in response to a detection of atleast one of the user moving farther away from the electronic device,the user not pausing near the electronic device, the user turning awaythe electronic device, the user facing away from the electronic device,or the user leaning away the electronic device.
 33. The electronicdevice of claim 21, wherein the persistent radar-based interactionmanager is further configured, responsive to causing the radar system toenter the interaction mode, to cause a display of the electronic deviceto increase a brightness level.
 34. The electronic device of claim 21,wherein the persistent radar-based interaction manager is furtherconfigured, responsive to causing the radar system to enter theinteraction mode, to cause a display of the electronic device to displayat least one of an authentication screen, a smart assistant, ornotifications.
 35. The electronic device of claim 21, wherein theinteraction mode enables the radar system to determine 3D gestures madeby the object in the radar field and process the 3D gestures, the 3Dgestures effective to enable the object to interact with the electronicdevice without verbal or touch input.
 36. The electronic device of claim35, wherein the 3D gestures comprise at least one of a scrollinggesture, a waving gesture, a pushing gesture, a reaching gesture, aturning gesture, or a spindle-twisting gesture.
 37. The electronicdevice of claim 35, wherein: the object comprises a user of theelectronic device; and the 3D gestures comprises a customized gesture ora customized combination of gestures defined by the user.
 38. Theelectronic device of claim 35, wherein: the object comprises a user ofthe electronic device; and the 3D gestures comprises at least one of ascrolling gesture made by the user moving a hand above the electronicdevice in a horizontal dimension, a waving gesture made by the userrotating an arm about an elbow of the arm, a pushing gesture made by theuser moving the hand above the electronic device in a verticaldimension, a reaching gesture made by the user moving the hand towardsthe electronic device, a turning gesture made by the user curlingfingers of the hand around an imaginary device and rotating the fingersin a clockwise or counter-clockwise fashion to mimic turning theimaginary device, and a twisting gesture made by the user rubbing athumb and at least one finger together.
 39. The electronic device ofclaim 38, wherein the 3D gestures are effective to enable the user tointeract with an application of the electronic device, control a userinterface for the application, take a photograph, interact withreminders or notifications, or manage a phone call.
 40. The electronicdevice of claim 35, the electronic device further comprising: anon-radar sensor configured to determine a context of the electronicdevice, wherein the persistent radar-based interaction manager isfurther configured to: interpret, based on the context of the electronicdevice, the 3D gestures as a particular action; and cause the particularaction to be performed on the electronic device.
 41. The electronicdevice of claim 40, wherein the non-radar sensor comprises at least oneof an accelerometer, a gyroscope, an inertial measurement unit, animage-capture device, a wireless communication transceiver, a display,an ambient light sensor, a microphone, or a touch-input sensor.
 42. Theelectronic device of claim 40, wherein: the object comprises a user ofthe electronic device; and the context of the electronic devicecomprises at least one of the electronic device being in a clothingpocket of a user, the electronic device being placed on a flat surface,the electronic device being held in a hand of the user, the electronicdevice being in an environment with a low amount of ambient light, amultimedia application on the electronic device playing media, anotification being available on the electronic device, an applicationwith scrollable content being displayed on the electronic device, or animage-capturing application open on the electronic device.
 43. Theelectronic device of claim 40, wherein: the electronic device comprisesa smartphone; the object comprises a user of the smartphone; the contextof the electronic device comprises the smartphone being in a clothingpocket of the user and a multimedia application on the smartphoneplaying media; and the 3D gestures comprise at least one of a horizontalswiping gesture effective to skip the media forward or backward, an airtap effective to pause or play the media, a vertical swiping gestureeffective to adjust a volume of the media, or a rotation gestureeffective to select media content.
 44. The electronic device of claim40, wherein: the electronic device comprises a smartphone; the objectcomprises a user of the smartphone; the context of the electronic devicecomprises the smartphone casting media to a remote device; and the 3Dgestures comprise at least one of a horizontal swiping gesture effectiveto skip the media forward or backward, an air tap effective to pause orplay the media, a vertical swiping gesture effective to adjust a volumeof the media, or a rotation gesture effective to select media content.45. The electronic device of claim 40, wherein: the electronic devicecomprises a smartphone; the object comprises a user of the smartphone;the context of the electronic device comprises the smartphone being heldaway from and facing the user and an image-capturing application open onthe smartphone; and the 3D gestures comprise at least one of ahorizontal swiping gesture effective to apply a filter, adjust a zoomlevel, or change a flash setting, an air tap effective to capture animage or a video, a vertical swiping gesture effective to adjust asetting of the image-capturing application, or a rotation gestureeffective to adjust another setting of the image-capturing application.46. The electronic device of claim 40, wherein: the electronic devicecomprises a smartphone; the object comprises a user of the smartphone;the context of the electronic device comprises the smartphone being on aflat surface and an application with content being displayed on adisplay of the smartphone; and the 3D gestures comprise at least one ofa vertical swiping gesture effective to scroll the content on thedisplay or a pinching gesture made by fingers of the user effective tozoom in or out on the content of the display.
 47. The electronic deviceof claim 40, wherein: the electronic device comprises a smartphone; theobject comprises a user of the smartphone; the context of the electronicdevice comprises the smartphone being held by the user and multipleapplications executing on the smartphone; and the 3D gestures compriseat least one of a horizontal swiping gesture effective to switch betweenthe multiple applications or an air tap effective to close a displayedapplication of the multiple applications.
 48. The electronic device ofclaim 40, wherein: the electronic device comprises a smartphone; theobject comprises a user of the smartphone; the context of the electronicdevice comprises the smartphone being on a flat surface and an alarm onthe smartphone is activated; and the 3D gestures comprise at least oneof a swiping gesture effective to turn off or delay the alarm, an airtap effective to delay or turn off the alarm, or a rotation gestureeffective to reset the alarm.
 49. The electronic device of claim 40,wherein: the electronic device comprises a smartphone; the objectcomprises a user of the smartphone; the context of the electronic devicecomprises the smartphone receiving a phone call; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective tosilence a ringer of the smartphone or send the phone call to voice mail,a vertical swiping gesture effective to answer the phone call, or arotation gesture effective to silence the ringer and open a menu ofpreset text responses.
 50. The electronic device of claim 40, wherein:the electronic device comprises a smartphone; the object comprises auser of the smartphone; the context of the electronic device comprisesthe smartphone being on a flat surface and the smartphone displaying anotification on a display; and the 3D gestures comprise at least one ofa swiping gesture effective to hide or postpone the notification, an airtap effective to cause the smartphone to display additional informationrelated to the notification, or a rotation gesture effective to dismissthe notification.
 51. The electronic device of claim 21, wherein theelectronic device comprises at least one of a smartphone, a tablet, alaptop, a desktop computer, a computing watch, computing spectacles, agaming system, a home-automation and control system, a television, anentertainment system, an audio system, an automobile, a drone, a trackpad, a drawing pad, a netbook, an e-reader, a home security system, or ahome appliance.
 52. A method implemented in an electronic device thatincludes a radar system, the method comprising: providing, by the radarsystem, a radar field; sensing, by the radar system, reflections from anobject in the radar field; analyzing the reflections from the object;providing, based on an analysis of the reflections, radar data;maintaining the radar system in an idle mode, the idle mode requiring nomore than approximately a first threshold of power; determining, basedon a first subset of the radar data, whether a presence of the object iswithin an awareness zone of the electronic device; responsive todetermining that the object is within the awareness zone, causing theradar system to enter an attention mode, the attention mode requiring nomore than a second threshold of power, the second threshold of powergreater than the first threshold of power; responsive to an entrance tothe attention mode and based on a second subset of the radar data,determining whether the object intends or does not intend to interactwith the electronic device; responsive to determining that the objectdoes not intend to interact with the electronic device, causing theradar system to exit the attention mode and enter the idle mode; andresponsive to determining that the object intends to interact with theelectronic device, causing the radar system to exit the attention modeand enter an interaction mode, the interaction mode requiring no morethan approximately a third threshold of power, the third threshold ofpower greater than the second threshold of power.
 53. The method ofclaim 52, wherein the first threshold of power is approximately eightmilliwatts (mW) and the third threshold of power is approximately 55 mWof power.
 54. The method of claim 52, wherein the first threshold ofpower is approximately two milliwatts (mW) and the third threshold ofpower is approximately 20 mW of power.
 55. The method of claim 52,wherein the first threshold of power is approximately one milliwatt (mW)and the third threshold of power is approximately three mW of power. 56.The method of claim 52, the method further comprising: adjusting a dutycycle at which the radar field of the radar system is maintained in theidle mode, the attention mode, or the interaction mode.
 57. The methodof claim 52, the method further comprising: responsive to a context ofthe electronic device, powering off the radar system.
 58. The method ofclaim 57, wherein: the electronic device comprises a smartphone; and thecontext of the electronic device comprises at least one of thesmartphone being maintained in a power-saving mode, the smartphone beingwithin a time period set by a user of the smartphone to power off theradar system, or the smartphone being placed face down on a surface. 59.The method of claim 52, wherein determining whether the object intendsor does not intend to interact with the electronic device comprisesdetermining, based on the second subset of the radar data, a position orposture of the object in relation to the electronic device.
 60. Themethod of claim 59, wherein the position or posture of the object inrelation to the electronic device comprises at least one of an absoluteposition of the object in relation to the electronic device, a change inthe absolute position of the object in relation to the electronicdevice, a relative velocity of the object in relation to the electronicdevice, a change in the relative velocity of the object in relation tothe electronic device, or a change in the posture of the object inrelation to the electronic device.
 61. The method of claim 59, wherein:the object comprises a user of the electronic device; and the positionor posture of the object in relation to the electronic device comprisesat least one of the user moving closer to or farther from the electronicdevice, the user pausing near the electronic device, the user turningtoward or away from the electronic device, the user leaning toward theelectronic device, the user waving toward or reaching for the electronicdevice, or the user pointing at the electronic device.
 62. The method ofclaim 61, the method further comprising: determining that the userintends to interact with the electronic device in response to adetection of at least one of the user moving closer to the electronicdevice, the user reaching for the electronic device, the user pausingnear the electronic device, the user turning toward the electronicdevice, the user leaning toward the electronic device, or the userpointing at the electronic device.
 63. The method of claim 61, themethod further comprising: determining that the user does not intend tointeract with the electronic device in response to a detection of atleast one of the user moving farther away from the electronic device,the user not pausing near the electronic device, the user turning awaythe electronic device, the user facing away from the electronic device,or the user leaning away the electronic device.
 64. The method of claim52, the method further comprising: responsive to causing the radarsystem to enter the interaction mode, causing a display of theelectronic device to increase a brightness level.
 65. The method ofclaim 52, the method further comprising: responsive to causing the radarsystem to enter the interaction mode, causing a display of theelectronic device to display at least one of an authentication screen, asmart assistant, or notifications.
 66. The method of claim 52, whereinthe interaction mode enables the radar system to determine 3D gesturesmade by the object in the radar field and process the 3D gestures, the3D gestures effective to enable the object to interact with theelectronic device without verbal or touch input.
 67. The method of claim66, wherein the 3D gestures comprise at least one of a scrollinggesture, a waving gesture, a pushing gesture, a reaching gesture, aturning gesture, or a spindle-twisting gesture.
 68. The method of claim66, wherein: the object comprises a user of the electronic device; andthe 3D gestures comprises a customized gesture or a customizedcombination of gestures defined by the user.
 69. The method of claim 66,wherein: the object comprises a user of the electronic device; and the3D gestures comprises at least one of a scrolling gesture made by theuser moving a hand above the electronic device in a horizontaldimension, a waving gesture made by the user rotating an arm about anelbow of the arm, a pushing gesture made by the user moving the handabove the electronic device in a vertical dimension, a reaching gesturemade by the user moving the hand towards the electronic device, aturning gesture made by the user curling fingers of the hand around animaginary device and rotating the fingers in a clockwise orcounter-clockwise fashion to mimic turning the imaginary device, and atwisting gesture made by the user rubbing a thumb and at least onefinger together.
 70. The method of claim 69, wherein the 3D gestures areeffective to enable the user to interact with an application of theelectronic device, control a user interface for the application, take aphotograph, interact with reminders or notifications, or manage a phonecall.
 71. The method of claim 66, the method further comprising:determining, by a non-radar sensor, a context of the electronic device;interpreting, based on the context of the electronic device, the 3Dgestures as a particular action; and causing the particular action to beperformed on the electronic device.
 72. The method of claim 71, whereinthe non-radar sensor comprises at least one of an accelerometer, agyroscope, an inertial measurement unit, an image-capture device, awireless communication transceiver, a display, an ambient light sensor,a microphone, or a touch-input sensor.
 73. The method of claim 71,wherein: the object comprises a user of the electronic device; and thecontext of the electronic device comprises at least one of theelectronic device being in a clothing pocket of a user, the electronicdevice being placed on a flat surface, the electronic device being heldin a hand of the user, the electronic device being in an environmentwith a low amount of ambient light, a multimedia application on theelectronic device playing media, a notification being available on theelectronic device, an application with scrollable content beingdisplayed on the electronic device, or an image-capturing applicationopen on the electronic device.
 74. The method of claim 71, wherein: theelectronic device comprises a smartphone; the object comprises a user ofthe smartphone; the context of the electronic device comprises thesmartphone being in a clothing pocket of the user and a multimediaapplication on the smartphone playing media; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective to skipthe media forward or backward, an air tap effective to pause or play themedia, a vertical swiping gesture effective to adjust a volume of themedia, or a rotation gesture effective to select media content.
 75. Themethod of claim 71, wherein: the electronic device comprises asmartphone; the object comprises a user of the smartphone; the contextof the electronic device comprises the smartphone casting media to aremote device; and the 3D gestures comprise at least one of a horizontalswiping gesture effective to skip the media forward or backward, an airtap effective to pause or play the media, a vertical swiping gestureeffective to adjust a volume of the media, or a rotation gestureeffective to select media content.
 76. The method of claim 71, wherein:the electronic device comprises a smartphone; the object comprises auser of the smartphone; the context of the electronic device comprisesthe smartphone being held away from and facing the user and animage-capturing application open on the smartphone; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective to applya filter, adjust a zoom level, or change a flash setting, an air tapeffective to capture an image or a video, a vertical swiping gestureeffective to adjust a setting of the image-capturing application, or arotation gesture effective to adjust another setting of theimage-capturing application.
 77. The method of claim 71, wherein: theelectronic device comprises a smartphone; the object comprises a user ofthe smartphone; the context of the electronic device comprises thesmartphone being on a flat surface and an application with content beingdisplayed on a display of the smartphone; and the 3D gestures compriseat least one of a vertical swiping gesture effective to scroll thecontent on the display or a pinching gesture made by fingers of the usereffective to zoom in or out on the content of the display.
 78. Themethod of claim 71, wherein: the electronic device comprises asmartphone; the object comprises a user of the smartphone; the contextof the electronic device comprises the smartphone being held by the userand multiple applications executing on the smartphone; and the 3Dgestures comprise at least one of a horizontal swiping gesture effectiveto switch between the multiple applications or an air tap effective toclose a displayed application of the multiple applications.
 79. Themethod of claim 71, wherein: the electronic device comprises asmartphone; the object comprises a user of the smartphone; the contextof the electronic device comprises the smartphone being on a flatsurface and an alarm on the smartphone is activated; and the 3D gesturescomprise at least one of a swiping gesture effective to turn off ordelay the alarm, an air tap effective to delay or turn off the alarm, ora rotation gesture effective to reset the alarm.
 80. The method of claim71, wherein: the electronic device comprises a smartphone; the objectcomprises a user of the smartphone; the context of the electronic devicecomprises the smartphone receiving a phone call; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective tosilence a ringer of the smartphone or send the phone call to voice mail,a vertical swiping gesture effective to answer the phone call, or arotation gesture effective to silence the ringer and open a menu ofpreset text responses.
 81. The method of claim 71, wherein: theelectronic device comprises a smartphone; the object comprises a user ofthe smartphone; the context of the electronic device comprises thesmartphone being on a flat surface and the smartphone displaying anotification on a display; and the 3D gestures comprise at least one ofa swiping gesture effective to hide or postpone the notification, an airtap effective to cause the smartphone to display additional informationrelated to the notification, or a rotation gesture effective to dismissthe notification.
 82. The method of claim 52, wherein the electronicdevice comprises at least one of a smartphone, a tablet, a laptop, adesktop computer, a computing watch, computing spectacles, a gamingsystem, a home-automation and control system, a television, anentertainment system, an audio system, an automobile, a drone, a trackpad, a drawing pad, a netbook, an e-reader, a home security system, or ahome appliance.
 83. A computer-readable storage media comprisingcomputer-executable instructions that, when executed, cause a processorof an electronic device that includes a radar system to: provide, by theradar system, a radar field; sense, by the radar system, reflectionsfrom an object in the radar field; analyze the reflections from theobject; provide, based on an analysis of the reflections, radar data;maintain the radar system in an idle mode, the idle mode requiring nomore than approximately a first threshold of power; determine, based ona first subset of the radar data, whether a presence of the object iswithin an awareness zone of the electronic device; responsive to adetermination that the object is within the awareness zone, cause theradar system to enter an attention mode, the attention mode requiring nomore than a second threshold of power, the second threshold of powergreater than the first threshold of power; responsive to an entrance tothe attention mode and based on a second subset of the radar data,determine whether the object intends or does not intend to interact withthe electronic device; responsive to a determination that the objectdoes not intend to interact with the electronic device, cause the radarsystem to exit the attention mode and enter the idle mode; andresponsive to a determination that the object intends to interact withthe electronic device, cause the radar system to exit the attention modeand enter an interaction mode, the interaction mode requiring no morethan approximately a third threshold of power, the third threshold ofpower greater than the second threshold of power.
 84. Thecomputer-readable storage media of claim 83, wherein the first thresholdof power is approximately eight milliwatts (mW) and the third thresholdof power is approximately 55 mW of power.
 85. The computer-readablestorage media of claim 83, wherein the first threshold of power isapproximately two milliwatts (mW) and the third threshold of power isapproximately 20 mW of power.
 86. The computer-readable storage media ofclaim 83, wherein the first threshold of power is approximately onemilliwatt (mW) and the third threshold of power is approximately threemW of power.
 87. The computer-readable storage media of claim 83, thecomputer-readable storage media comprising further computer-executableinstructions that, when executed, cause the processor of the electronicdevice to: adjust a duty cycle at which the radar field of the radarsystem is maintained in the idle mode, the attention mode, or theinteraction mode.
 88. The computer-readable storage media of claim 83,the computer-readable storage media comprising furthercomputer-executable instructions that, when executed, cause theprocessor of the electronic device to: responsive to a context of theelectronic device, power off the radar system.
 89. The computer-readablestorage media of claim 88, wherein: the electronic device comprises asmartphone; and the context of the electronic device comprises at leastone of the smartphone being maintained in a power-saving mode, thesmartphone being within a time period set by a user of the smartphone topower off the radar system, or the smartphone being placed face down ona surface.
 90. The computer-readable storage media of claim 83, thecomputer-readable storage media, in determining whether the objectintends or does not intend to interact with the electronic device,comprising further computer-executable instructions that, when executed,cause the processor of the electronic device to: determine, based on thesecond subset of the radar data, a position or posture of the object inrelation to the electronic device.
 91. The computer-readable storagemedia of claim 90, wherein the position or posture of the object inrelation to the electronic device comprises at least one of an absoluteposition of the object in relation to the electronic device, a change inthe absolute position of the object in relation to the electronicdevice, a relative velocity of the object in relation to the electronicdevice, a change in the relative velocity of the object in relation tothe electronic device, or a change in the posture of the object inrelation to the electronic device.
 92. The computer-readable storagemedia of claim 90, wherein: the object comprises a user of theelectronic device; and the position or posture of the object in relationto the electronic device comprises at least one of the user movingcloser to or farther from the electronic device, the user pausing nearthe electronic device, the user turning toward or away from theelectronic device, the user leaning toward the electronic device, theuser waving toward or reaching for the electronic device, or the userpointing at the electronic device.
 93. The computer-readable storagemedia of claim 92, the computer-readable storage media comprisingfurther computer-executable instructions that, when executed, cause theprocessor of the electronic device to: determine that the user intendsto interact with the electronic device in response to a detection of atleast one of the user moving closer to the electronic device, the userreaching for the electronic device, the user pausing near the electronicdevice, the user turning toward the electronic device, the user leaningtoward the electronic device, or the user pointing at the electronicdevice.
 94. The computer-readable storage media of claim 92, thecomputer-readable storage media comprising further computer-executableinstructions that, when executed, cause the processor of the electronicdevice to: determine that the user does not intend to interact with theelectronic device in response to a detection of at least one of the usermoving farther away from the electronic device, the user not pausingnear the electronic device, the user turning away the electronic device,the user facing away from the electronic device, or the user leaningaway the electronic device.
 95. The computer-readable storage media ofclaim 83, the computer-readable storage media comprising furthercomputer-executable instructions that, when executed, cause theprocessor of the electronic device to: responsive to causing the radarsystem to enter the interaction mode, cause a display of the electronicdevice to increase a brightness level.
 96. The computer-readable storagemedia of claim 83, the computer-readable storage media comprisingfurther computer-executable instructions that, when executed, cause theprocessor of the electronic device to: responsive to causing the radarsystem to enter the interaction mode, cause a display of the electronicdevice to display at least one of an authentication screen, a smartassistant, or notifications.
 97. The computer-readable storage media ofclaim 83, wherein the interaction mode enables the radar system todetermine 3D gestures made by the object in the radar field and processthe 3D gestures, the 3D gestures effective to enable the object tointeract with the electronic device without verbal or touch input. 98.The computer-readable storage media of claim 97, wherein the 3D gesturescomprise at least one of a scrolling gesture, a waving gesture, apushing gesture, a reaching gesture, a turning gesture, or aspindle-twisting gesture.
 99. The computer-readable storage media ofclaim 97, wherein: the object comprises a user of the electronic device;and the 3D gestures comprises a customized gesture or a customizedcombination of gestures defined by the user.
 100. The computer-readablestorage media of claim 97, wherein: the object comprises a user of theelectronic device; and the 3D gestures comprises at least one of ascrolling gesture made by the user moving a hand above the electronicdevice in a horizontal dimension, a waving gesture made by the userrotating an arm about an elbow of the arm, a pushing gesture made by theuser moving the hand above the electronic device in a verticaldimension, a reaching gesture made by the user moving the hand towardsthe electronic device, a turning gesture made by the user curlingfingers of the hand around an imaginary device and rotating the fingersin a clockwise or counter-clockwise fashion to mimic turning theimaginary device, and a twisting gesture made by the user rubbing athumb and at least one finger together.
 101. The computer-readablestorage media of claim 100, wherein the 3D gestures are effective toenable the user to interact with an application of the electronicdevice, control a user interface for the application, take a photograph,interact with reminders or notifications, or manage a phone call. 102.The computer-readable storage media of claim 97, the computer-readablestorage media comprising further computer-executable instructions that,when executed, cause the processor of the electronic device to:determine, using a non-radar sensor, a context of the electronic device;interpret, based on the context of the electronic device, the 3Dgestures as a particular action; and cause the particular action to beperformed on the electronic device.
 103. The computer-readable storagemedia of claim 102, wherein the non-radar sensor comprises at least oneof an accelerometer, a gyroscope, an inertial measurement unit, animage-capture device, a wireless communication transceiver, a display,an ambient light sensor, a microphone, or a touch-input sensor.
 104. Thecomputer-readable storage media of claim 102, wherein: the objectcomprises a user of the electronic device; and the context of theelectronic device comprises at least one of the electronic device beingin a clothing pocket of a user, the electronic device being placed on aflat surface, the electronic device being held in a hand of the user,the electronic device being in an environment with a low amount ofambient light, a multimedia application on the electronic device playingmedia, a notification being available on the electronic device, anapplication with scrollable content being displayed on the electronicdevice, or an image-capturing application open on the electronic device.105. The computer-readable storage media of claim 102, wherein: theelectronic device comprises a smartphone; the object comprises a user ofthe smartphone; the context of the electronic device comprises thesmartphone being in a clothing pocket of the user and a multimediaapplication on the smartphone playing media; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective to skipthe media forward or backward, an air tap effective to pause or play themedia, a vertical swiping gesture effective to adjust a volume of themedia, or a rotation gesture effective to select media content.
 106. Thecomputer-readable storage media of claim 102, wherein: the electronicdevice comprises a smartphone; the object comprises a user of thesmartphone; the context of the electronic device comprises thesmartphone casting media to a remote device; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective to skipthe media forward or backward, an air tap effective to pause or play themedia, a vertical swiping gesture effective to adjust a volume of themedia, or a rotation gesture effective to select media content.
 107. Thecomputer-readable storage media of claim 102, wherein: the electronicdevice comprises a smartphone; the object comprises a user of thesmartphone; the context of the electronic device comprises thesmartphone being held away from and facing the user and animage-capturing application open on the smartphone; and the 3D gesturescomprise at least one of a horizontal swiping gesture effective to applya filter, adjust a zoom level, or change a flash setting, an air tapeffective to capture an image or a video, a vertical swiping gestureeffective to adjust a setting of the image-capturing application, or arotation gesture effective to adjust another setting of theimage-capturing application.
 108. The computer-readable storage media ofclaim 102, wherein: the electronic device comprises a smartphone; theobject comprises a user of the smartphone; the context of the electronicdevice comprises the smartphone being on a flat surface and anapplication with content being displayed on a display of the smartphone;and the 3D gestures comprise at least one of a vertical swiping gestureeffective to scroll the content on the display or a pinching gesturemade by fingers of the user effective to zoom in or out on the contentof the display.
 109. The computer-readable storage media of claim 102,wherein: the electronic device comprises a smartphone; the objectcomprises a user of the smartphone; the context of the electronic devicecomprises the smartphone being held by the user and multipleapplications executing on the smartphone; and the 3D gestures compriseat least one of a horizontal swiping gesture effective to switch betweenthe multiple applications or an air tap effective to close a displayedapplication of the multiple applications.
 110. The computer-readablestorage media of claim 102, wherein: the electronic device comprises asmartphone; the object comprises a user of the smartphone; the contextof the electronic device comprises the smartphone being on a flatsurface and an alarm on the smartphone is activated; and the 3D gesturescomprise at least one of a swiping gesture effective to turn off ordelay the alarm, an air tap effective to delay or turn off the alarm, ora rotation gesture effective to reset the alarm.
 111. Thecomputer-readable storage media of claim 102, wherein: the electronicdevice comprises a smartphone; the object comprises a user of thesmartphone; the context of the electronic device comprises thesmartphone receiving a phone call; and the 3D gestures comprise at leastone of a horizontal swiping gesture effective to silence a ringer of thesmartphone or send the phone call to voice mail, a vertical swipinggesture effective to answer the phone call, or a rotation gestureeffective to silence the ringer and open a menu of preset textresponses.
 112. The computer-readable storage media of claim 102,wherein: the electronic device comprises a smartphone; the objectcomprises a user of the smartphone; the context of the electronic devicecomprises the smartphone being on a flat surface and the smartphonedisplaying a notification on a display; and the 3D gestures comprise atleast one of a swiping gesture effective to hide or postpone thenotification, an air tap effective to cause the smartphone to displayadditional information related to the notification, or a rotationgesture effective to dismiss the notification.
 113. Thecomputer-readable storage media of claim 83, wherein the electronicdevice comprises at least one of a smartphone, a tablet, a laptop, adesktop computer, a computing watch, computing spectacles, a gamingsystem, a home-automation and control system, a television, anentertainment system, an audio system, an automobile, a drone, a trackpad, a drawing pad, a netbook, an e-reader, a home security system, or ahome appliance.